EP4791739A1

EP4791739A1 - Synthetic process for the manufacture of ecteinascidin compounds

Info

Publication number: EP4791739A1
Application number: EP23789286.4A
Authority: EP
Inventors: María Jesús MARTÍN LÓPEZ; Guillermo TARAZONA RAMOS; Maria Del Carmen Cuevas Marchante
Original assignee: Pharmamar SA
Current assignee: Pharmamar SA
Priority date: 2023-10-09
Filing date: 2023-10-09
Publication date: 2026-08-19
Also published as: AU2023469117A1; CN121986103A; WO2025077996A1

Abstract

The present invention relates processes to convert compounds of Formula (I) to Formula (II), and compounds of Formula (I).

Description

Synthetic process for the manufacture of ecteinascidin compounds

FIELD OF THE INVENTION

The present invention relates to synthetic processes, and in particular relates to synthetic processes for the manufacture of ecteinascidin compounds.

BACKGROUND TO THE INVENTION

Ecteinascidins are a group of naturally occurring marine compounds and synthetic analogs thereof, which are well identified and structurally characterized, and are disclosed to have antibacterial and cytotoxic properties. See for example, European Patent 309.477; WO 03/66638; WO 03/08423; WO 01/77115; WO 03/014127; WO 2018/197663; R. Sakai et al., 1992, Proc. Natl. Acad. Sci. USA 89, pages 11456-11460; R. Menchaca et al., 2003, J. Org. Chem. 68(23), pages 8859-8866; and I. Manzanares et al., 2001 , Curr. Med. Chem. Anti-Cancer Agents, 1 , pages 257-276; and references therein. Examples of ecteinascidins are provided by ET-743, ET-729, ET-745, ET-759A, ET-759B, ET- 759C, ET-770, ET-815, ET-731 , ET-745B, ET-722, ET-736, ET-738, ET-808, ET-752, ET-594, ET-552, ET-637, ET-652, ET-583, ET-597, ET-596, ET-639, ET-641 , and synthetic analogs thereof, such as acetylated forms, formylated forms, methylated forms, and oxide forms.

However, there remains a need to develop more efficient processes, in particular hemisynthetic routes, to manufacture ecteinascidin compounds and related compounds. The present invention addresses this need.

SUMMARY OF THE INVENTION

According to an aspect of the present invention there is provided a process for the synthesis of an ecteinascidin compound, comprising a step of oxidizing a reaction mixture comprising a compound of Formula I to give a compound of Formula II: wherein:

Ri is OH or CN;

R2 is hydrogen or Prot^NH; and

R3 is hydrogen or Prot^OH, wherein Prot^NH is a protecting group for amino, and Prot^OH is a protecting group for OH.

The present invention has identified that compound HQ-3 is highly insoluble in both organic and aqueous media, forming precipitates and causing reductions in overall process yield. By reducing the amounts of compound HQ-3 produced as a downstream intermediate, in particular by oxidizing compounds of Formula I to compounds of Formula II at an early stage of ecteinascidin compound synthesis, a reduction in the amount of precipitate produced during the reaction process can be obtained. This thereby leads to a more efficient and higher yielding process, particularly at the plant scale.

In a preferred aspect, Ri is OH.

In a preferred aspect, Ri is CN.

In a preferred aspect, R2 is hydrogen.

In a preferred aspect, R2 is Prot^NH.

In a preferred aspect, Prot^NH is selected from allylcarbamate (Alloc), 2,2,2-trichloroethylcarbamate (Troc), benzylcarbamate (Cbz), 9-fluorenylmethyl-carbamate (Fmoc), CONHPh, CSNHPh, and t- butylcarbamate (Boc), preferably t-butylcarbamate (Boc).

In an alternative aspect, Prot^NH does not include CONHPh.

In an alternative aspect, Prot^NH is selected from allylcarbamate (Alloc), 2,2,2-trichloroethylcarbamate (Troc), benzylcarbamate (Cbz), 9-fluorenylmethyl-carbamate (Fmoc), CSNHPh, and t-butylcarbamate (Boc), preferably t-butylcarbamate (Boc).

In a preferred aspect, R3 is hydrogen.

In a preferred aspect, oxidation is conducted using an oxidizing agent, biochemical oxidation or electrochemical oxidation.

In a preferred aspect, the oxidizing agent is selected from the group consisting of: metal oxidizing agents (such as Cr(VI) compounds, Mn(IV) compounds, Mn(VII) compounds, Fe(lll) compounds, Cu(ll) compounds, Ag(l) compounds, Pb(IV) compounds, Ce(IV) compounds), molecular oxygen, hydrogen peroxide, hypochlorite salts (such as NaOCI and Ca(OCI)2), chlorite salts, 1 ,4-benzoquinone and 2,3- dichloro-5,6-dicyano-1 ,4-benzoquinone, or a combination thereof.

In a preferred aspect, the oxidizing agent is selected from molecular oxygen, hydrogen peroxide, 1 ,4- benzoquinone and a metal oxidizing agent, or a combination thereof.

In a preferred aspect, the metal oxidizing agent is a transition metal oxidizing agent. In a preferred aspect, the transition metal is Fe, Cu or Mn.

In a preferred aspect, the transition metal oxidizing agent is selected from Fe(lll) compounds (e.g. FeCh, or K3[Fe(CN)e]), Cu(ll) compounds (e.g. CuSC ), Mn (III) compounds (e.g. Mn(OAc)s), Mn(IV) compounds (e.g. MnC>2), and Mn(VII) compounds (e.g. KMnC ). In a preferred aspect, the Fe(lll) compound is FeCh.

In a preferred aspect, the oxidizing agent may be a halogen based oxidizing agent. The halogen may be iodine (e.g. I2 and HIO3).

In a preferred aspect, the oxidizing agent may be a quinone (e.g. chloranil).

In a preferred aspect, a number of equivalents of the oxidizing agent with respect to the compound of Formula I in the reaction mixture is about 1.0 equiv. to about 15.0 equiv., preferably about 1.2 equiv. to about 10.0 equiv., more preferably about 1 .5 equiv. to about 8.0 equiv., even more preferably about 2.0 equiv. to about 5.0 equiv.

In a preferred aspect, the oxidizing agent is molecular oxygen.

In a preferred aspect, the molecular oxygen is provided by exposing the reaction mixture to a reaction atmosphere comprising molecular oxygen.

In a preferred aspect, a stream comprising molecular oxygen is bubbled through the reaction mixture during the step of oxidizing the reaction mixture comprising the compound of Formula I to give the compound of Formula II.

In a preferred aspect, the reaction is conducted at a pH of about 3.0 to about 9.0, preferably about 3.5 to about 8.5, more preferably about 4.0 to about 8.0.

In a preferred aspect, the biochemical oxidation is catalysed by hydroquinone oxidase or cells exhibiting hydroquinone oxidase activity.

In a preferred aspect, the reaction mixture further comprises a compound according to Formula II; preferably wherein R1 in the compound according to Formula I in the reaction mixture is the same as R1 in the compound according to Formula II in the reaction mixture, and/orwherein R2 in the compound according to Formula I in the reaction mixture is the same as R2 in the compound according to Formula II in the reaction mixture, and/or wherein R3 in the compound according to Formula I in the reaction mixture is the same as R3 in the compound according to Formula II in the reaction mixture; more preferably wherein R1 , R2 and R3 in the compound according to Formula I in the reaction mixture are the same as R1 , R2 and R3 in the compound according to Formula II in the reaction mixture.

In a preferred aspect, the step of oxidizing the reaction mixture comprising the compound of Formula I to give the compound of Formula II is conducted at about 0 °C to about 100 °C, preferably about 0 °C to about 80 °C, more preferably about 5 °C to about 60 °C, even more preferably about 5 °C to about 40 °C, yet even more preferably about 10 °C to about 30 °C, most preferably about 10 °C to about 25 °C.

In a preferred aspect, the process further comprises a step of conducting a cyanation reaction to convert R1 from OH to CN, before or after the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II; preferably after the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II. In a preferred aspect, the process further comprises a step of conducting an amino protection reaction to convert R2 from hydrogen to Prot^NH, before or afterthe step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II; preferably after the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II.

In a preferred aspect, R1 in Formula I is OH and R2 in Formula I is hydrogen, and the process: further comprises a step of conducting a cyanation reaction to convert R1 from OH to CN immediately after the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II; and further comprises a step of conducting an amino protection reaction to convert R2 from hydrogen to Prot^NH immediately after the step of conducting the cyanation reaction to convert R1 from OH to CN.

In a preferred aspect, R1 in Formula I is CN and R2 in Formula I is hydrogen, and the process: further comprises a step of conducting a cyanation reaction to convert R1 from OH to CN immediately before the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II; and further comprises a step of conducting an amino protection reaction to convert R2 from hydrogen to Prot^NH immediately after the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II.

In a preferred aspect, the step of oxidizing the reaction mixture comprising the compound of Formula I to give the compound of Formula II, and the step of conducting the cyanation reaction to convert R1 from OH to CN, are conducted as a one-pot reaction.

According to another aspect of the present invention there is provided a compound according to Formula I: wherein R1 to R3 are as defined herein, with the proviso that when R2 is CONHPh then R3 is hydrogen.

In a preferred aspect, the compound is of formula:

According to another aspect of the present invention there is provided a compound of formula:

5

DETAILED DESCRIPTION OF THE INVENTION

The following apply to all aspects of the present invention.

General chemical definitions

In the compounds of the present invention, the alkyl groups may be branched or unbranched, and preferably have from 1 to about 12 carbon atoms. One more preferred class of alkyl groups has from 1 to about 6 carbon atoms. Even more preferred are alkyl groups having 1 , 2, 3 or 4 carbon atoms. Methyl, ethyl, n-propyl, isopropyl and butyl, including n-butyl, isobutyl, sec-butyl and tert-butyl are particularly preferred alkyl groups in the compounds of the present invention.

In the compounds of the present invention, the alkenyl groups may be branched or unbranched, have one or more double bonds and from 2 to about 12 carbon atoms. One more preferred class of alkenyl groups has from 2 to about 6 carbon atoms. Even more preferred are alkenyl groups having 2, 3 or 4 carbon atoms. Ethenyl, 1 -propenyl, 2-propenyl, 1 -methylethenyl, 1-butenyl, 2-butenyl, and 3-butenyl are particularly preferred alkenyl groups in the compounds of the present invention.

In the compounds of the present invention, the alkynyl groups may be branched or unbranched, have one or more triple bonds and from 2 to about 12 carbon atoms. One more preferred class of alkynyl groups has from 2 to about 6 carbon atoms. Even more preferred are alkynyl groups having 2, 3 or 4 carbon atoms.

Suitable aryl groups in the compounds of the present invention include single and multiple ring compounds, including multiple ring compounds that contain separate and/or fused aryl groups. Typical aryl groups contain from 1 to 3 separated and/or fused rings and from 6 to about 18 carbon ring atoms. Preferably aryl groups contain from 6 to about 10 carbon ring atoms. Specially preferred aryl groups included substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl, substituted or unsubstituted phenanthryl and substituted or unsubstituted anthryl.

Suitable heterocyclic groups include heteroaromatic and heteroalicyclic groups containing from 1 to 3 separated and/or fused rings and from 5 to about 18 ring atoms. Preferably heteroaromatic and heteroalicyclic groups contain from 5 to about 10 ring atoms, most preferably 5, 6, or 7 ring atoms. Suitable heteroaromatic groups in the compounds of the present invention contain one, two or three heteroatoms selected from N, O or S atoms and include, e.g., coumarinyl including 8-coumarinyl, quinolyl including 8-quinoly I, isoquinolyl, pyridyl, pyrazinyl, pyrazolyl, pyrimidinyl, furyl, pyrrolyl, thienyl, thiazolyl, isothiazolyl, triazolyl, tetrazolyl, isoxazolyl, oxazolyl, imidazolyl, indolyl, isoindolyl, indazolyl, indolizinyl, phthalazinyl, pteridyl, purinyl, oxadiazolyl, thiadiazolyl, furazanyl, pyridazinyl, triazinyl, cinnolinyl, benzimidazolyl, benzofuranyl, benzofurazanyl, benzothiophenyl, benzothiazolyl, benzoxazolyl, quinazolinyl, quinoxalinyl, naphthyridinyl and furopyridyl. Suitable heteroalicyclic groups in the compounds of the present invention contain one, two or three heteroatoms selected from N, O or S and include, e.g., pyrrolidinyl, tetrahydrofuranyl, tetrahydrothienyl, tetrahydrothiopyranyl, piperidyl, morpholinyl, thiomorpholinyl, thioxanyl, piperazinyl, azetidinyl, oxetanyl, thietanyl, homopiperidyl, oxepanyl, thiepanyl, oxazepinyl, diazepinyl, thiazepinyl, 1 ,2,3,6-tetrahydropyridyl, 2-pirrolinyl, 3- pyrrolinyl, indolinyl, 2/7-pyranyl, 4/7-pyranyl, dioxanyl, 1 ,3-dioxolanyl, pyrazolinyl, dithianyl, dithiolanyl, dihydropyranyl, dihydrothienyl, dihydrofuranyl, pyrazolidinyl, imidazolinyl, imidazolidinyl, 3- azabicyclo[3.1 .0]hexyl, 3-azabicyclo[4.1.0]heptyl, 3/7-indolyl, and quinolizinyl.

The groups above mentioned may be substituted at one or more available positions by one or more suitable groups such as OR’, =O, SR’, SOR’, SO₂R’, NO₂, NHR’, NR’R’, =N-R’, NHCOR’, N(COR’)₂, NHSO₂R’, NR^,C(=NR’)NR^,R’, CN, halogen, COR’, COOR’, OCOR’, OCONHR’, OCONR’R’, CONHR’, CONR’R’, protected OH, protected amino, protected SH, substituted or unsubstituted Ci-Ci₂ alkyl, substituted or unsubstituted C₂-Ci₂ alkenyl, substituted or unsubstituted C₂-Ci₂ alkynyl, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic group, where each of the R’ groups is independently selected from the group consisting of hydrogen, OH, NO₂, NH₂, SH, CN, halogen, COH, COalkyl, CO₂H, substituted or unsubstituted Ci-Ci₂ alkyl, substituted or unsubstituted C₂-Ci₂ alkenyl, substituted or unsubstituted C₂-Ci₂ alkynyl, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic group. Where such groups are themselves substituted, the substituents may be chosen from the foregoing list. In addition, where there are more than one R’ groups on a substituent, each R’ may be the same or different.

In the compounds for the present invention, the halogen substituents include F, Cl, Br, and I.

The term “pharmaceutically acceptable salt” refers to any pharmaceutically acceptable salt which, upon administration to the patient is capable of providing (directly or indirectly) a compound as described herein. However, it will be appreciated that non-pharmaceutically acceptable salts also fall within the scope of the invention since those may be useful in the preparation of pharmaceutically acceptable salts. The preparation of salts can be carried out by methods known in the art.

For instance, pharmaceutically acceptable salts of the compounds provided herein are synthesized from the parent compounds, which contain a basic or acidic moiety, by conventional chemical methods. Generally, such salts are, for example, prepared by reacting the free acid or base of these compounds with a stoichiometric amount of the appropriate base or acid in water or in an organic solvent or in a mixture of both. Generally, nonaqueous media like ether, ethyl acetate, ethanol, 2-propanol or acetonitrile are preferred. Examples of the acid addition salts include mineral acid addition salts such as, for example, hydrochloride, hydrobromide, hydroiodide, sulfate, nitrate, phosphate, and organic acid addition salts such as, for example, acetate, trifluoroacetate, maleate, fumarate, citrate, oxalate, succinate, tartrate, malate, mandelate, methanesulfonate and p-toluenesulfonate. Examples of the alkali addition salts include inorganic salts such as, for example, sodium, potassium, calcium and ammonium salts, and organic alkali salts such as, for example, ethylenediamine, ethanolamine, /V,/V- dialkylenethanolamine, triethanolamine and basic aminoacids salts.

The compounds of the invention may be in crystalline or amorphous form either as free compounds or as solvates (e.g. hydrates) and it is intended that all forms are within the scope of the present invention. Methods of solvation are generally known within the art.

Stereoisomerism about the asymmetric carbons with unspecified stereochemistry is possible, therefore in such cases the asymmetric carbons can have (R) or (S) configuration. All diastereomers generated by a specific configuration of such asymmetric carbons in conjunction with the other asymmetric carbons present in the molecule, and mixtures thereof, are considered within the scope of the present invention. Stereoisomerism about the double bond (geometric isomerism) is also possible, therefore in some cases the molecule could exist as (E)-isomer or (Z)-isomer. If the molecule contains several double bonds, each double bond will have its own stereoisomerism, that could be the same or different than the stereoisomerism of the other double bonds of the molecule. Furthermore, compounds referred to herein may exist as atropoisomers. The single stereoisomers including diastereoisomers, geometric isomers and atropoisomers of the compounds referred to herein, and mixtures thereof fall within the scope of the present invention.

In addition, compounds referred to herein may exist in isotopically-labelled forms. All pharmaceutically acceptable salts, esters and isotopically labelled forms of the compounds referred to herein, and mixtures thereof, are considered within the scope of the present invention.

Protected forms of the compounds disclosed herein are considered within the scope of the present invention. Suitable protecting groups are well known for the skilled person in the art. A general review of protecting groups in organic chemistry is provided by Wuts, PGM and Greene TW in Protecting Groups in Organic Synthesis, 4^th Ed. Wiley-lnterscience, and by Kocienski PJ in Protecting Groups, 3^rd Ed. Georg Thieme Verlag. These references provide sections on protecting groups for OH, amino and SH groups. All these references are incorporated by reference in their entirety.

Within the scope of the present invention an OH protecting group is defined to be the O-bonded moiety resulting from the protection of the OH through the formation of a suitable protected OH group. Examples of such protected OH groups include ethers, silyl ethers, esters, sulfonates, sulfenates and sulfinates, carbonates, and carbamates. In the case of ethers the protecting group for the OH can be selected from methyl, methoxymethyl, methylthiomethyl, (phenyldimethylsilyl)methoxymethyl, benzyloxymethyl, p-methoxybenzyloxymethyl, [(3,4-dimethoxybenzyl)oxy]methyl, p- nitrobenzyloxymethyl, o-nitrobenzyloxymethyl, [(R)-1 -(2-nitrophenyl)ethoxy]methyl, (4- methoxyphenoxy)methyl, guaiacolmethyl, [(p-phenylphenyl)oxy]methyl, f-butoxymethyl, 4- pentenyloxymethyl, siloxymethyl, 2-methoxyethoxymethyl, 2-cyanoethoxymethyl, bis(2- chloroethoxy)methyl, 2,2,2-trichloroethoxymethyl, 2-(trimethylsilyl)ethoxymethyl, menthoxymethyl, O- bis(2-acetoxy-ethoxy)methyl, tetrahydropyranyl, fluorous tetrahydropyranyl, 3-bromotetrahydropyranyl, tetrahydrothiopyranyl, 1 -methoxycyclohexyl, 4-methoxytetrahydropyranyl, 4-methoxy- tetrahydrothiopyranyl, 4-methoxytetrahydrothiopyranyl S,S-dioxide, 1 -[(2-chloro-4-methyl)-phenyl]-4- methoxypiperidin-4-yl, 1 -(2-fluorophenyl)-4-methoxypiperidin-4-yl, 1 -(4-chlorophenyl)-4- methoxypiperidin-4-yl, 1 ,4-dioxan-2-yl, tetrahydrofuranyl, tetrahydrothiofuranyl, 2, 3, 3a, 4, 5, 6, 7, 7a- octahydro-7,8,8-trimethyl-4,7-methanobenzofuran-2-yl, 1 -ethoxyethyl, 1 -(2-chloroethoxy)ethyl, 2- hydroxyethyl, 2-bromoethyl, 1-[2-(trimethylsilyl)ethoxy]ethyl, 1-methyl-1 -methoxyethyl, 1-methyl-1- benzyloxyethyl, 1-methyl-1-benzyloxy-2-fluoroethyl, 1-methyl-1 -phenoxyethyl, 2,2,2-trichloroethyl, 1 ,1- dianisyl-2,2,2-trichloroethyl, 1 ,1 ,1 ,3,3,3-hexafluoro-2-phenylisopropyl, 1-(2-cyanoethoxy)ethyl, 2- trimethylsilylethyl, 2-(benzylthio)ethyl, 2-(phenylselenyl)ethyl, f-butyl, cyclohexyl, 1-methyl-1 ’- cyclopropylmethyl, allyl, prenyl, cinnamyl, 2-phenallyl, propargyl, p-chlorophenyl, p-methoxyphenyl, p- nitrophenyl, 2,4-dinitrophenyl, 2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenyl, benzyl, p-methoxybenzyl, 3,4-dimethoxybenzyl, 2,6-dimethoxybenzyl, o-nitrobenzyl, p-nitrobenzyl, pentadienylnitrobenzyl, pentadienylnitropiperonyl, halobenzyl, 2,6-dichlorobenzyl, 2,4-dichlorobenzyl, 2,6-difluorobenzyl, p- cyanobenzyl, fluorous benzyl, 4-fluorousalkoxybenzyl, trimethylsilylxylyl, p-phenylbenzyl, 2-phenyl-2- propyl, p-acylaminobenzyl, p-azidobenzyl, 4-azido-3-chlorobenzyl, 2-trifluoromethylbenzyl, 4- trifluoromethylbenzyl, p-(methylsulfinyl)benzyl, p-siletanylbenzyl, 4-acetoxybenzyl, 4-(2- trimethylsilyl)ethoxymethoxybenzyl, 2-naphthylmethyl, 2-picolyl, 4-picolyl, 3-methyl-2-picolyl A/-oxide, 2-quinolinylmethyl, 6-methoxy-2-(4-methylphenyl)-4-quinolinemethyl, 1-pyrenylmethyl, diphenylmethyl, 4-methoxydiphenylmethyl, 4-phenyldiphenylmethyl, p,p’-dinitrobenzhydryl, 5-dibenzosuberyl, triphenylmethyl, tris(4-f-butylphenyl)methyl, a-naphthyldiphenylmethyl, p- methoxyphenyldiphenylmethyl, di(p-methoxyphenyl)phenyl-methyl, tri(p-methoxyphenyl)methyl, 4-(4’- bromophenacyloxy)phenyldiphenylmethyl, 4,4’,4”-tris(4,5-dichlorophthalimidophenyl)methyl, 4, 4’, 4”- tris(levulinoyloxyphenyl)methyl, 4,4’,4”-tris(benzoyloxyphenyl)methyl, 4,4’-dimethoxy-3”-[/V- (imidazolylmethyl)]trityl, 4,4’-dimethoxy-3”-[/V-(imidazolylethyl)carbamoyl]trityl, bis(4-methoxyphenyl)- 1 ’-pyrenylmethyl, 4-(17-tetrabenzo[a,c,g,/]fluorenylmethyl)-4,4”-dimethoxytrityl, 9-anthryl, 9-(9- phenyl)xanthenyl, 9-phenylthioxanthyl, 9-(9-phenyl-10-oxo)anthryl, 1 ,3-benzodithiolan-2-yl, 4,5- bis(ethoxycarbonyl)-[1 ,3]-dioxolan-2-yl, benzisothiazolyl S,S-dioxide. In the case of silyl ethers the protecting group for the OH can be selected from trimethylsilyl, triethylsilyl, triisopropylsilyl, dimethylisopropylsilyl, diethylisopropylsilyl, dimethylhexylsilyl, 2-norbornyldimethylsilyl, t- butyldimethylsilyl, f-butyldiphenylsilyl, tribenzylsilyl, tri-p-xylylsilyl, triphenylsilyl, diphenylmethylsilyl, di- f-butylmethylsilyl, bis(f-butyl)-1-pyrenylmethoxysilyl, tris(trimethylsilyl)silyl, (2- hydroxystyryl)dimethylsilyl, (2-hydroxystyryl)diisopropylsilyl, f-butylmethoxyphenylsilyl, t- butoxydiphenylsilyl, 1 ,1 ,3,3-tetraisopropyl-3-[2-(triphenylmethoxy) ethoxy]disiloxane-1-yl, and fluorous silyl. In the case of esters the protecting group for the OH together with the oxygen atom of the unprotected OH to which it is attached form an ester that can be selected from formate, benzoylformate, acetate, chloroacetate, dichloroacetate, trichloroacetate, trichloroacetamidate, trifluoroacetate, methoxyacetate, triphenylmethoxyacetate, phenoxyacetate, p-chlorophenoxyacetate, phenylacetate, diphenylacetate, 3-phenylpropionate, bisfluorous chain type propanoyl, 4-pentenoate, 4- oxopentanoate, 4,4-(ethylenedithio)pentanoate, 5[3-bis(4-methoxyphenyl)hydro- xymethylphenoxy]levulinate, pivaloate, 1-adamantoate, crotonate, 4-methoxycrotonate, benzoate, p- phenylbenzoate, 2,4,6-trimethylbenzoate, 4-bromobenzoate, 2,5-difluorobenzoate, p-nitrobenzoate, picolinate, nicotinate, 2-(azidomethyl)benzoate, 4-azido-butyrate, (2-azidomethyl)phenylacetate, 2- {[(tritylthio)oxy]methyl}benzoate, 2-{[(4-methoxytritylthio)oxy]methyl}benzoate, 2-

{[methyl(tritylthio)amino]methyl}benzoate, 2-{{[(4-methoxytrityl)thio]methylamino}methyl}benzoate, 2- (allyloxy)phenylacetate, 2-(prenyloxymethyl)benzoate, 6-(levulinyloxymethyl)-3-methoxy-2- nitrobenzoate, 6-(levulinyloxymethyl)-3-methoxy-4-nitrobenzoate, 4-benzyloxybutyrate, 4- trialkylsilyloxy-butyrate, 4-acetoxy-2,2-dimethylbutyrate, 2,2-dimethyl-4-pentenoate, 2-iodobenzoate, 4-nitro-4-methylpentanoate, o-(dibromomethyl)benzoate, 2-formylbenzenesulfonate, 4-(methylthio- methoxy)butyrate, 2-(methylthiomethoxymethyl)benzoate, 2-(chloroacetoxymethyl)benzoate, 2-[(2- chloroacetoxy)ethyl]benzoate, 2-[2-(benzyloxy)ethyl]benzoate, 2-[2-(4-methoxybenzyl- oxy)ethyl]benzoate, 2,6-dichloro-4-methylphenoxyacetate, 2,6-dichloro-4-(1 ,1 ,3,3- tetramethylbutyl)phenoxyacetate, 2,4-bis(1 ,1-dimethylpropyl)phenoxyacetate, chlorodiphenyl-acetate, isobutyrate, monosuccinoate, (E)-2-methyl-2-butenoate, o-(methoxycarbonyl)benzoate, a-naphthoate, nitrate, alkyl A/,A/,A/’,A/’-tetramethylphosphorodiamidate, and 2-chlorobenzoate. In the case of sulfonates, sulfenates and sulfinates the protecting group for the OH together with the oxygen atom of the unprotected OH to which it is attached form a sulfonate, sulfenate or sulfinates that can be selected from sulfate, allylsulfonate, methanesulfonate, benzylsulfonate, tosylate, 2-[(4- nitrophenyl)ethyl]sulfonate, 2-trifluoromethylbenzenesulfonate, 4-monomethoxytritylsulfenate, alkyl 2,4-dinitrophenylsulfenate, 2,2,5,5-tetramethylpyrrolidin-3-one-1-sulfinate, and dimethylphosphinothioyl. In the case of carbonates the protecting group for the OH together with the oxygen atom of the unprotected OH to which it is attached form a carbonate that can be selected from methyl carbonate, methoxymethyl carbonate, 9-fluorenylmethyl carbonate, ethyl carbonate, bromoethyl carbonate, 2-(methylthiomethoxy)ethyl carbonate, 2,2,2-trichloroethyl carbonate, 1 ,1-dimethyl-2,2,2- trichloroethyl carbonate, 2-(trimethylsilyl)ethyl carbonate, 2-[dimethyl(2-naphthylmethyl)silyl]ethyl carbonate, 2-(phenylsulfonyl)ethyl carbonate, 2-(triphenylphosphonio)ethyl carbonate, c/s-[4- [[(methoxytrityl)sulfenyl]oxy]tetrahydrofuran-3-yl]oxy carbonate, isobutyl carbonate, f-butyl carbonate, vinyl carbonate, allyl carbonate, cinnamyl carbonate, propargyl carbonate, p-chlorophenyl carbonate, p-nitrophenyl carbonate, 4-ethoxy-1 -naphthyl carbonate, 6-bromo-7-hydroxycoumarin-4-ylmethyl carbonate, benzyl carbonate, o-nitrobenzyl carbonate, p-nitrobenzyl carbonate, p-methoxybenzyl carbonate, 3,4-dimethoxybenzyl carbonate, anthraquinon-2-ylmethyl carbonate, 2-dansylethyl carbonate, 2-(4-nitrophenyl)ethyl carbonate, 2-(2,4-dinitrophenyl)ethyl carbonate, 2-(2- nitrophenyl)propyl carbonate, 2-(3,4-methylenedioxy-6-nitrophenyl)propyl carbonate, 2-cyano-1- phenylethyl carbonate, 2-(2-pyridyl)amino-1-phenylethyl carbonate, 2-[/V-methyl-/V-(2-pyridyl)]amino-1- phenylethyl carbonate, phenacyl carbonate, 3’,5’-dimethoxybenzoin carbonate, methyl dithiocarbonate, and S-benzyl thiocarbonate. And in the case of carbamates the protecting group for OH together with the oxygen atom of the unprotected OH to which it is attached forms a carbamate that can be selected from dimethyl thiocarbamate, A/-phenyl carbamate, and A/-methyl-A/-(o-nitrophenyl) carbamate. Preferred OH protecting groups include methoxyethoxymethyl ether (MEM) and methoxymethyl ether (MOM).

Within the scope of the present invention an amino protecting group is defined to be the A/-bonded moiety resulting from the protection of the amino group through the formation of a suitable protected amino group. Examples of protected amino groups include carbamates, ureas, amides, heterocyclic systems, /V-alkyl amines, A/-alkenyl amines, /V-alkynyl amines, /V-aryl amines, imines, enamines, N- metal derivatives, N-N derivatives, N-P derivatives, N-Si derivatives, and N-S derivatives. In the case of carbamates the protecting group for the amino group together with the amino group to which it is attached form a carbamate that can be selected from methyl carbamate, ethyl carbamate, 9- fluorenylmethyl carbamate, 2,6-di-f-butyl-9-fluorenylmethyl carbamate, 2,7- bis(trimethylsilyl)fluorenylmethyl carbamate, 9-(2-sulfo)fluorenylmethyl carbamate, 9-(2,7- dibromo)fluorenylmethyl carbamate, 17-tetrabenzo[a,c,g,/]fluorenylmethyl carbamate, 2-chloro-3- indenylmethyl carbamate, benz[/]inden-3-ylmethyl carbamate, 1 ,1-dioxobenzo[b]-thiophene-2-ylmethyl carbamate, 2-methylsulfonyl-3-phenyl-1-prop-2-enyl carbamate, 2,7-di-f-butyl-[9,(10,10-dioxo- 10,10,10,10-tetrahydrothioxanthyl)]methyl carbamate, 2,2,2-trichloroethyl carbamate, 2- trimethylsilylethyl carbamate, (2-phenyl-2-trimethylsilyl)ethyl carbamate, 2-phenylethyl carbamate, 2- chloroethyl carbamate, 1 ,1-dimethyl-2-haloethyl carbamate, 1 ,1-dimethyl-2,2-dibromoethyl carbamate, 1 ,1-dimethyl-2,2,2-trichloroethyl carbamate, 2-(2'-pyridyl)ethyl carbamate, 2-(4'-pyridyl)ethyl carbamate, 2,2-bis(4'-nitrophenyl)ethyl carbamate, 2-[(2-nitrophenyl)dithio]-1 -phenylethyl carbamate, 2-(/V,/V-dicyclohexylcarboxamido)ethyl carbamate, f-butyl carbamate, fluorous BOC carbamate, 1- adamantyl carbamate, 2-adamantyl carbamate, 1-(1-adamantyl)-1 -methylethyl carbamate, 1-methyl-1- (4-byphenylyl)ethyl carbamate, 1-(3,5-di-f-butylphenyl)-1-methylethyl carbamate, triisopropylsilyloxy carbamate, vinyl carbamate, allyl carbamate, prenyl carbamate, 1 -isopropylallyl carbamate, cinnamyl carbamate, 4-nitrocinnamyl carbamate, 3-(3'-pyridyl)prop-2-enyl carbamate, hexadienyl carbamate, propargyl carbamate, 1 ,4-but-2-ynyl biscarbamate, 8-quinolyl carbamate, A/-hydroxypiperidinyl carbamate, alkyl dithiocarbamate, benzyl carbamate, 3,5-di-f-butylbenzyl carbamate, p-methoxybenzyl carbamate, p-nitrobenzyl carbamate, p-bromobenzyl carbamate, p-chlorobenzyl carbamate, 2,4- dichlorobenzyl carbamate, 4-methylsulfinylbenzyl carbamate, 4-trifluoromethylbenzyl carbamate, fluorous benzyl carbamate, 2-naphthylmethyl carbamate, 9-anthrylmethyl carbamate, diphenylmethyl carbamate, 4-phenylacetoxybenzyl carbamate, 4-azidobenzyl carbamate, 4-azido-methoxybenzyl carbamate, m-chloro-p-acyloxybenzyl carbamate, p-(dihydroxyboryl)-benzyl carbamate, 5- benzisoxazolylmethyl carbamate, 2-(trifluoromethyl)-6-chromonylmethyl carbamate, 2-methylthioethyl carbamate, 2-methylsulfonylethyl carbamate, 2-(p-toluenesulfonyl)ethyl carbamate, 2-(4- nitrophenylsulfonyl)ethyl carbamate, 2-(2,4-dinitrophenylsulfonyl)ethyl carbamate, 2-(4- trifluoromethylphenylsulfonyl)ethyl carbamate, [2-(1 ,3-dithianyl)]methyl carbamate, 2-phosphonioethyl carbamate, 2-[phenyl(methyl)sulfonio]ethyl carbamate, 1-methyl-1-(triphenylphosphonio)ethyl carbamate, 1 ,1 -dimethyl-2-cyanoethyl carbamate, 2-dansylethyl carbamate, 2-(4-nitrophenyl)ethyl carbamate, 4-methylthiophenyl carbamate, 2,4-dimethylthiophenyl carbamate, m-nitrophenyl carbamate, 3,5-dimethoxybenzyl carbamate, 1-methyl-1-(3,5-dimethoxyphenyl)ethyl carbamate, a- methylnitropiperonyl carbamate, o-nitrobenzyl carbamate, 3,4-dimethoxy-6-nitrobenzyl carbamate, phenyl(o-nitrophenyl)methyl carbamate, 2-nitrophenylethyl carbamate, 6-nitroveratryl carbamate, 4- methoxyphenacyl carbamate, 3',5'-dimethoxybenzoin carbamate, 9-xanthenylmethyl carbamate, A/- methyl-A/-(o-nitrophenyl) carbamate, f-amyl carbamate, 1 -methylcyclobutyl carbamate, 1- methylcyclohexyl carbamate, 1 -methyl-1 -cyclopropylmethyl carbamate, cyclobutyl carbamate, cyclopentyl carbamate, cyclohexyl carbamate, isobutyl carbamate, isobornyl carbamate, cyclopropylmethyl carbamate, p-decyloxybenzyl carbamate, diisopropylmethyl carbamate, 2,2- dimethoxy-carbonylvinyl carbamate, o-(A/,A/-dimethylcarboxamido)benzyl carbamate, 1 ,1-dimethyl-3- (A/,A/-dimethyl-carboxamido)propyl carbamate, butynyl carbamate, 1 ,1-dimethylpropynyl carbamate, 2- iodoethyl carbamate, 1 -methyl-1 -(4'-pyridyl)ethyl carbamate, 1 -methyl-1 -(p-phenylazophenyl)ethyl carbamate, p-(p-methoxyphenylazo)benzyl carbamate, p-(phenylazo)benzyl carbamate, 2,4,6- trimethylbenzyl carbamate, isonicotinyl carbamate, 4-(trimethyl-ammonium)benzyl carbamate, p- cyanobenzyl carbamate, di(2-pyridyl)methyl carbamate, 2-furanylmethyl carbamate, phenyl carbamate, 2,4,6-tri-f-butylphenyl carbamate, 1 -methyl-1 -phenylethyl carbamate, and S-benzyl thiocarbamate. In the case of ureas the protecting groups for the amino group can be selected from phenothiazinyl-(I O)- carbonyl, A/'-p-toluenesulfonylaminocarbonyl, A/'-phenylaminocarbonyl, 4- hydroxyphenylaminocarbonyl, 3-hydroxytryptaminocarbonyl, and A/'-phenylaminothiocarbonyl. In the case of amides the protecting group for the amino together with the amino group to which it is attached form an amide that can be selected from formamide, acetamide, chloroacetamide, trichloroacetamide, trifluoroacetamide, phenylacetamide, 3-phenylpropanamide, pent-4-enamide, picolinamide, 3- pyridylcarboxamide, A/-benzoylphenylalanyl amide, benzamide, p-phenylbenzamide, o- nitrophenylacetamide, 2,2-dimethyl-2-(o-nitrophenyl)acetamide, o-nitrophenoxyacetamide, 3-(o- nitrophenyl)propanamide, 2-methyl-2-(o-nitrophenoxy)propanamide, 3-methyl-3-nitrobutanamide, o- nitrocinnamide, o-nitrobenzamide, 3-(4-f-butyl-2,6-dinitrophenyl)-2,2-dimethylpropanamide, o- (benzoyloxymethyl)benzamide, 2-(acetoxymethyl)benzamide, 2-[(f- butyldiphenylsiloxy)methyl]benzamide, 3-(3',6'-dioxo-2',4',5'-trimethylcyclohexa-1 ',4'-diene)-3,3- dimethylpropionamide, o-hydroxy-frans-cinnamide, 2-methyl-2-(o-phenylazophenoxy)propanamide, 4- chlorobutanamide, acetoacetamide, 3-(p-hydroxyphenyl)propanamide, (Af- dithiobenzyloxycarbonylamino)acetamide, and AAacetylmethionine amide. In the case of heterocyclic systems the protecting group for the amino group together with the amino group to which it is attached form a heterocyclic system that can be selected from 4,5-diphenyl-3-oxazolin-2-one, AAphthalimide, A/- dichlorophthalimide, AAtetrachlorophthalimide, A/-4-nitrophthalimide, AAthiodiglycoloyl, A/- dithiasuccinimide, A/-2,3-diphenylmaleimide, A/-2,3-dimethylmaleimide, A/-2,5-dimethylpyrrole, N-2,5- bis(triisopropylsiloxy)pyrrole, A/-1 ,1 ,4,4-tetramethyldisilylazacyclopentane adduct, A/-1 , 1 ,3,3- tetramethyl-1 ,3-disilaisoindoline, AAdipheny Isilyldiethy lene, A/-5-substituted-1 ,3-dimethyl-1 ,3,5- triazacyclohexan-2-one, A/-5-substituted-1 ,3-benzyl-1 ,3,5-triazacyclohexan-2-one, 1 -substituted 3,5- dinitro-4-pyridone, and 1 ,3,5-dioxazine. In the case of AAalky I , A/-alkenyl, AAalky ny I or N-ary I amines the protecting group for the amino group can be selected from A/-methyl, A/-f-butyl, A/-allyl, A/-prenyl, N- cinnamyl, AAphenylallyl, A/-propargyl, AZ-methoxymethyl, A/-[2-(trimethylsilyl)ethoxy]methyl, A/-3- acetoxypropyl, AAcyanomethyl, A/-2-azanorbornenes, A/-benzyl, A/-4-methoxybenzyl, A/-2,4- dimethoxybenzyl, A/-2-hydroxybenzyl, AAferrocenylmethyl, A/-2,4-dinitrophenyl, o-methoxyphenyl, p- methoxyphenyl, A/-9-phenylfluorenyl, A/-fluorenyl, A/-2-picolylamine N'-oxide, A/-7-methoxycoumar-4- ylmethyl, A/-diphenylmethyl, A/-bis(4-methoxyphenyl)methyl, A/-5-dibenzosuberyl, A/-triphenylmethyl, AZ- (4-methylphenyl)diphenylmethyl, and A/-(4-methoxyphenyl)diphenylmethyl. In the case of imines the protecting group for the amino group can be selected from A/-1 ,1 -dimethylthiomethylene, Inbenzylidene, N-p-methoxy benzylidene, A/-diphenylmethylene, A/-[2-pyridyl)mesityl]methylene, AZ-CA^A/¹- dimethylaminomethylene), A/-(A/\A/'-dibenzylaminomethylene), AZ-(AZ'-f-butylaminomethylene), A/.A/¹- isopropylidene, A/-p-nitrobenzylidene, A/-salicylidene, A/-5-chlorosalicylidene, A/-(5-chloro-2- hydroxyphenyl)phenylmethylene, AAcyclohexylidene, and A/-f-butylidene. In the case of enamines the protecting group for the amino group can be selected from A/-(5,5-dimethyl-3-oxo-1-cyclohexenyl), AZ- 2,7-dichloro-9-fluorenylmethylene, A/-1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl, A/-(1 ,3-dimethyl- 2,4,6-(1 Z7,3/7,5/-/)-trioxopyrimidine-5-ylidene)-methyl, A/-4,4,4-trifluoro-3-oxo-1 -butenyl, and A/-(1 - isopropyl-4-nitro-2-oxo-3-pyrrolin-3-yl). In the case of N-metal derivatives the protecting group for the amino group can be selected from N-borane, AAdiphenylborinic ester, A/-diethylborinic ester, A/-9- borabicyclononane, AAdifluoroborinic ester, and 3,5-bis(trifluoromethyl)phenylboronic acid; and also including A/-phenyl(pentacarbonylchromium)carbenyl, A/-phenyl(pentacarbonyltungsten)carbenyl, AZ- methyl(pentacarbonylchromium)carbenyl, A/-methyl(pentacarbonyltungsten)carbenyl, A/-copper chelate, A/-zinc chelate, and a 18-crown-6-derivative. In the case of N-N derivatives the protecting group for the amino group together with the amino group to which it is attached form a N-N derivative that can be selected from AAnitroamino, AAnitrosoamino, amine A/-oxide, azide, triazene derivative, and AZ- trimethylsilylmethyl-A/-benzylhydrazine. In the case of N-P derivatives the protected group for the amino group together with the amino group to which it is attached form a N-P derivative that can be selected from diphenylphosphinamide, dimethylthiophosphinamide, diphenylthiophosphinamide, dialkyl phosphoramidate, dibenzyl phosphoramidate, diphenyl phosphoramidate, and iminotriphenylphosphorane. In the case of N-Si derivatives the protecting group for the NH2 can be selected from f-butyldiphenylsilyl and triphenylsilyl. In the case of N-S derivatives the protected amino group can be selected from N-sulfenyl or N-sulfonyl derivatives. The N-sulfenyl derivatives can be selected from benzenesulfenamide, 2-nitrobenzenesulfenamide, 2,4-dinitrobenzenesulfenamide, pentachlorobenzenesulfenamide, 2-nitro-4-methoxybenzenesulfenamide, triphenylmethylsulfenamide, 1-(2,2,2-trifluoro-1 ,1-diphenyl)ethylsulfenamide, and A/-3-nitro-2-pyridinesulfenamide. The N-sulfonyl derivatives can be selected from methanesulfonamide, trifluoromethanesulfonamide, t- butylsulfonamide, benzylsulfonamide, 2-(trimethylsilyl) ethanesulfonamide, p-toluenesulfonamide, benzenesulfonamide, o-anisylsulfonamide, 2-nitrobenzenesulfonamide, 4-nitrobenzenesulfonamide, 2,4-dinitrobenzenesulfonamide, 2-naphthalenesulfonamide, 4-(4',8'- dimethoxynaphthylmethyl)benzenesulfonamide, 2-(4-methylphenyl)-6-methoxy-4-methylsulfonamide, 9-anthracenesulfonamide, pyridine-2-sulfonamide, benzothiazole-2-sulfonamide, phenacylsulfonamide, 2,3,6-trimethyl-4-methoxybenzenesulfonamide, 2,4,6- trimethoxybenzenesulfonamide, 2,6-dimethyl-4-methoxy-benzenesulfonamide, pentamethylbenzenesulfonamide, 2,3,5,6-tetramethyl-4-methoxyben-zenesulfonamide, 4- methoxybenzenesulfonamide, 2,4,6-trimethylbenzenesulfonamide, 2,6-dimethoxy-4- methylbenzenesulfonamide, 3-methoxy-4-f-butylbenzenesulfonamide, and 2, 2, 5,7,8- pentamethylchroman-6-sulfonamide.

Preferred amino protecting groups include allylcarbamate (Alloc), 2,2,2-trichloroethylcarbamate (Troc), benzylcarbamate (Cbz), 9-fluorenylmethyl-carbamate (Fmoc), A/'-phenylaminocarbonyl (CONHPh), N'- phenylaminothiocarbonyl (CSNHPh), and t-butylcarbamate (Boc). Most preferred is t-butylcarbamate.

Within the scope of the present invention a protecting group for SH is defined to be the S-bonded moiety resulting from the protection of the SH group through the formation of a suitable a protected SH group. Examples of such protected SH groups include thioethers, disulfides, silyl thioethers, thioesters, thiocarbonates, and thiocarbamates. In the case of thioethers the protecting group for the SH can be selected from S-alkyl, S-benzyl, S-p-methoxybenzyl, S-o-hydroxybenzyl, S-p-hydroxybenzyl, S-o- acetoxybenzyl, S-p-acetoxybenzyl, S-p-nitrobenzyl, S-o-nitrobenzyl, S-2,4,6-trimethylbenzyl, S-2,4,6,- trimethoxybenzyl, S-4-picolyl, S-2-picolyl-/V-oxide, S-2-quinolinylmethyl, S-9-anthrylmethyl, S-9- fluorenylmethyl, S-xanthenyl, S-ferrocenylmethyl, S-diphenylmethyl, S-bis(4-methoxyphenyl)methyl, S- 5-dibenzosuberyl, S-triphenylmethyl, 4-methoxytrityl, S-diphenyl-4-pyridylmethyl, S-phenyl, S-2,4- dinitrophenyl, S-2-quinolyl, S-f-butyl, S-1-adamantyl, S-methoxymethyl, S-isobutoxymethyl, S- benzyloxymethyl, S-1 -ethoxyethyl, S-2-tetrahydropyranyl, S-benzylthiomethyl, S-phenylthiomethyl, S- acetamidomethyl (Acm), S-trimethylacetamidomethyl, S-benzamidomethyl, S- allyloxycarbonylaminomethyl, S-A/-[2,3,5,6-tetrafluoro-4-(A/'-piperidino)-phenyl-A/- allyloxycarbonylaminomethyl, S-phthalimidomethyl, S-phenylacetamidomethyl, S-acetylmethyl, S- carboxymethyl, S-cyanomethyl, S-(2-nitro-1-phenyl)ethyl, S-2-(2,4-dinitrophenyl)ethyl, S-2-(4'- pyridyl)ethyl, S-2-cyanoethyl, S-2-(trimethylsilyl)ethyl, S-2,2-bis(carboethoxy)ethyl, S-(1-m-nitrophenyl- 2-benzoyl)ethyl, S-2-phenylsulfonylethyl, S-1-(4-methylphenylsulfonyl)-2-methylprop-2-yl, and S-p- hydroxyphenacyl. In the case of disulfides the protected SH group can be selected from S-ethyl disulfide, S-f-butyl disulfide, S-2-nitrophenyl disulfide, S-2,4-dinitrophenyl disulfide, S-2- phenylazophenyl disulfide, S-2-carboxyphenyl disulfide, and S-3-nitro-2-py ridyl disulfide. In the case of silyl thioethers the protecting group for the SH can be selected from the list of groups that was listed above for the protection of OH with silyl ethers. In the case of thioesters the protecting group for the SH can be selected from S-acetyl, S-benzoyl, S-2-methoxyisobutyryl, S-trifluoroacetyl, S-/V-[[p-biphenylyl)- isopropyloxy]carbonyl]-A/-methyl-y-aminothiobutyrate, and S-A/-(f-butoxycarbonyl)-A/-methyl-y- aminoth iobutyrate. In the case of thiocarbonate protecting group for the SH can be selected from S- 2,2,2-trichloroethoxycarbonyl, S-f-butoxycarbonyl, S-benzyloxycarbonyl, S-p- methoxybenzyloxycarbonyl, and S-fluorenylmethylcarbonyl. In the case of thiocarbamate the protected SH group can be selected from S-(/V-ethylcarbamate) and S-(/V-methoxymethylcarbamate).

Preferred SH protecting groups include substituted or unsubstituted S-9-fluorenylmethyl. Most preferred is S-9-fluorenylmethyl (Fm).

The mention of these groups should not be interpreted as a limitation of the scope of the invention, since they have been mentioned as a mere illustration of protecting groups for OH, amino and SH groups, but further groups having said function may be known by the skilled person in the art, and they are to be understood to be also encompassed by the present invention.

The term “ecteinascidin compound” may refer to compounds of Formula E:

E wherein:

R101 and R104 are independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alkynyl, C(=O)R^10c, C(=O)OR^10b, C(=O)NR^10dR^10e, and a protecting group for OH;

R102 is selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alkynyl, C(=O)R^10c, C(=O)OR^10b, C(=O)NR^10dR^10e, and a protecting group for amino;

R103 is CN or OH;

R105 and R106 together to the carbon to which they are attached form a group:

(a) C(=O);

(b) CH(ORW7) or CH(NRIOSRIO9) wherein R107 is selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocyclic group, and a protecting group for OH; and Rios and R109 are independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocyclic group, and a protecting group for amino;

(c) a group of formula: wherein

X101 and X102 are independently selected from hydrogen and substituted or unsubstituted Ci- 012 alkyl; Rno and Rm are independently selected from hydrogen, C(=O)R^10c, C(=O)OR^10b, C(=O)NR^10dR^10e, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, and substituted or unsubstituted C2-C12 alkynyl; or

(d) a group of formula: wherein

X is -NR112- or -O-; hydrogen, OR^b, OC(=O)R^C, OC(=O)OR^b, OC(=O)NR^dR^e, SR^f, SOR^C, SO₂R^C, C(=O)R^c, C(=O)OR^b, C(=O)NR^dR^e, NO₂, NR^dR^e, N(R^d)C(=O)R^c, N(R^d)-OR^b, C(R^c)=NOR^b, N(R^d)C(=O)OR^b, N(R^d)C(=O)NR^dR^e, CN, halogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alkynyl, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic group;

Y101 is selected from hydrogen, OR^10b, OC(=O)R^10c, OC(=O)OR^10b, OC(=O)NR^10dR^10e, SR^10f, SOR^10c, SO₂R^10C, C(=O)R^10C, C(=O)OR^10b, C(=O)NR^10dR^10e, NO₂, NR^10dR^10e, N(R^10d)C(=O)R^10c, N(R^10d)-OR^10b, C(R^10c)=NOR^10b, N(R^10d)C(=O)OR^10b, N(R^10d)C(=O)NR^10dR^10e, CN, halogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alkynyl, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic group;

Y102 and Y103 are independently selected from hydrogen and substituted or unsubstituted Ci- 012 alkyl;

R112 and R113 are independently selected from hydrogen, C(=O)R^10c, C(=O)OR^10b, C(=O)NR^10dR^10e, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, and substituted or unsubstituted C2-C12 alkynyl; and each R^10b is independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocyclic group, and a protecting group for OH; each R^10c is independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alkynyl, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic group; each R^10d and R^10e is independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocyclic group, and a protecting group for amino; each R^10f is independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocyclic group, and a protecting group for SH; or a pharmaceutically acceptable salt thereof.

Preferably, R101 may be hydrogen or the same as R4 as described herein.

Preferably, R102 may be methyl.

Preferably, R104 may be the same as Rs as described herein.

Preferably, X101 may be the same as Xi as described herein.

Preferably, X102 may be the same as X2 as described herein.

Preferably, Rno may be hydrogen.

Preferably, Rm may be hydrogen.

Preferably, Y101 may be the same as Y1 as described herein.

Preferably, Y102 may be the same as Y2 as described herein.

Preferably, Y103 may be the same as Y3 as described herein.

Preferably, R112 may be hydrogen.

Preferably, R113 may be hydrogen.

Oxidation reactions of compounds of Formula I to Formula II and related synthetic steps

According to an aspect of the present invention, there is provided a process for the synthesis of an ecteinascidin compound, comprising a step of oxidizing a reaction mixture comprising a compound of Formula I to give a compound of Formula II: wherein:

R1 is OH or CN;

R2 is hydrogen or Prot^NH; and

In some preferred embodiments, R1 is OH. In other preferred embodiments, R1 is CN. In some preferred embodiments, R2 is hydrogen. In other preferred embodiments, R2 is Prot^NH.

Preferably, Prot^NH is selected from allylcarbamate (Alloc), 2,2,2-trichloroethylcarbamate (Troc), benzylcarbamate (Cbz), 9-fluorenylmethyl-carbamate (Fmoc), CONHPh, CSNHPh, and t- butylcarbamate (Boc), more preferably t-butylcarbamate (Boc).

Preferably, R3 is hydrogen.

Preferably, oxidation is conducted using an oxidizing agent, biochemical oxidation or electrochemical oxidation.

Preferably, the oxidizing agent is selected from the group consisting of: metal oxidizing agents (such as Cr(VI) compounds, Mn(IV) compounds, Mn(VII) compounds, Fe(lll) compounds, Cu(ll) compounds, Ag(l) compounds, Pb(IV) compounds, Ce(IV) compounds), inorganic catalytic metals as ruthenium, cobalt and the like, molecular oxygen, hydrogen peroxide, hypochlorite salts (such as NaOCI and Ca(OCI)2), chlorite salts, 1 ,4-benzoquinone and 2,3-dichloro-5,6-dicyano-1 ,4-benzoquinone, or a combination thereof. Preferred examples of Cr(VI) compounds include dichromate salts (e.g. potassium dichromate, pyridinium dichromate), chromium trioxide and chlorochromate salts (e.g. pyridinium chlorochromate). Preferred examples of Mn(IV) compounds include manganese dioxide. Preferred examples Mn(VII) compounds include permanganate salts (e.g. potassium permanganate). Preferred Fe(lll) compounds include iron(lll) acetate, iron(lll) chloride, iron(lll) bromide, iron(lll) sulfate and iron(lll) nitrate. Preferred Cu(ll) compounds include copper(ll) acetate, copper(ll) chloride, copper(ll) bromide, copper(ll) sulfate and copper(ll) nitrate. Preferred Ag(l) compounds include silver(l) oxide. Preferred Pb(IV) compounds include lead dioxide, lead(IV) acetate and lead(IV) chloride. Preferred Ce(IV) compounds include cerium ammonium nitrate. More preferably, the oxidizing agent is selected from molecular oxygen, hydrogen peroxide, 1 ,4-benzoquinone and a metal oxidizing agent, or a combination thereof.

Preferably, the metal oxidizing agent is a transition metal oxidizing agent. More preferably, the transition metal oxidizing agent is selected from Fe(lll) compounds (e.g. FeCh) and Cu(ll) compounds (e.g. CUSO4). Even more preferably, the Fe(lll) compound is FeCh.

Preferably, a number of equivalents of the oxidizing agent with respect to the compound of Formula I in the reaction mixture is about 1 .0 equiv. to about 15.0 equiv., preferably about 1 .2 equiv. to about 10.0 equiv., more preferably about 1.5 equiv. to about 8.0 equiv., even more preferably about 2.0 equiv. to about 5.0 equiv. When the reaction mixture further comprises a compound according to Formula II, the number of equivalents of the oxidizing agent may be calculated with respect to the combined amount of the compound of Formula I and the compound of Formula II present in the reaction mixture.

Preferably, the oxidizing agent is molecular oxygen. More preferably, when the oxidizing agent is molecular oxygen, the reaction is conducted at a pH of about 3.0 to about 9.0, preferably about 5.0 to about 8.5, more preferably about 6.0 to about 8.0.

Preferably, the molecular oxygen is provided by exposing the reaction mixture to a reaction atmosphere comprising molecular oxygen. The reaction atmosphere may comprise between about 5% to about 100% of molecular oxygen, preferably between about 6% to about 50% of molecular oxygen, more preferably between about 7% to about 40% of molecular oxygen, even more preferably between about 8% to about 30% of molecular oxygen by volume.

Preferably, a stream comprising molecular oxygen is bubbled through the reaction mixture during the step of oxidizing the reaction mixture comprising the compound of Formula I to give the compound of Formula II. The stream may comprise between about 5% to about 100% of molecular oxygen, preferably between about 6% to about 50% of molecular oxygen, more preferably between about 7% to about 40% of molecular oxygen, even more preferably between about 8% to about 30% of molecular oxygen by volume.

Preferably, the reaction is catalysed by inorganic catalytic metals. Preferred examples of inorganic catalytic metals include as ruthenium, cobalt and the like.

Preferably, the reaction is conducted at a pH of about 3.0 to about 9.0, preferably about 3.5 to about 8.5, more preferably about 4.0 to about 8.0.

Preferably, the biochemical oxidation is catalysed by hydroquinone oxidase or cells exhibiting hydroquinone oxidase activity.

Preferably, the reaction mixture further comprises a compound according to Formula II; preferably wherein Ri in the compound according to Formula I in the reaction mixture is the same as Ri in the compound according to Formula II in the reaction mixture, and/or wherein R2 in the compound according to Formula I in the reaction mixture is the same as R2 in the compound according to Formula II in the reaction mixture, and/or wherein R3 in the compound according to Formula I in the reaction mixture is the same as R3 in the compound according to Formula II in the reaction mixture; more preferably wherein Ri, R2 and R3 in the compound according to Formula I in the reaction mixture are the same as Ri, R2 and R3 in the compound according to Formula II in the reaction mixture.

Preferably, the step of oxidizing the reaction mixture comprising the compound of Formula I to give the compound of Formula II is conducted at about 0 °C to about 100 °C, preferably about 0 °C to about 80 °C, more preferably about 5 °C to about 60 °C, even more preferably about 5 °C to about 40 °C, yet even more preferably about 10 °C to about 30 °C, most preferably about 10 °C to about 25 °C.

Preferably, the process further comprises a step of conducting a cyanation reaction to convert Ri from OH to CN, before or after the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II; preferably afterthe step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II.

Preferably, the step of conducting a cyanation reaction to convert Ri from OH to CN is conducted using a metal cyanide, preferably an alkali metal cyanide, most preferably KCN or NaCN.

Preferably, the process further comprises a step of conducting an amino protection reaction to convert R2 from hydrogen to Prot^NH, before or after the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II; preferably after the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II.

Preferably, Ri in Formula I is OH and R2 in Formula I is hydrogen, and the process: further comprises a step of conducting a cyanation reaction to convert R1 from OH to CN immediately after the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II; and further comprises a step of conducting an amino protection reaction to convert R2 from hydrogen to Prot^NH immediately after the step of conducting the cyanation reaction to convert R1 from OH to CN.

Preferably, R1 in Formula I is CN and R2 in Formula I is hydrogen, and the process: further comprises a step of conducting a cyanation reaction to convert R1 from OH to CN immediately before the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II; and further comprises a step of conducting an amino protection reaction to convert R2 from hydrogen to Prot^NH immediately after the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II.

Preferably, the step of oxidizing the reaction mixture comprising the compound of Formula I to give the compound of Formula II, and the step of conducting the cyanation reaction to convert R1 from OH to CN, are conducted as a one-pot reaction.

In an preferred alternative embodiment, the compound according to Formula I does not include Compound HQ-3.

In a preferred embodiment, the reaction mixture is a fermentation broth or is obtained from a fermentation broth. The fermentation broth may be produced from Pseudomonas fluorescens. The Pseudomonas fluorescens may be a modified strain. The Pseudomonas fluorescens may be a modified such that it produces Compound I. The Pseudomonas fluorescens may be a modified such that it produces Compound I and Compound II. In embodiments, the fermentation broth may be obtained by following the teaching of Munakata et al. Journal of Antibiotics, 1983, 36(10), 1279-1283, US4440752, JPS59225189A, and/or Meyers E et. al. Journal of Antibiotics, 1983, 36(2), 190-193. The fermentation broth may contain a mixture of Compound I and Compound II.

In an alternative embodiment, the reaction mixture is an extract from a fermentation broth. An extract from a fermentation broth includes a concentrate. An extract from a fermentation broth may be a methanolic concentrate.

Further synthetic steps

The oxidation reactions of compounds of Formula I to Formula II as described herein may be utilised in the early stages of ecteinascidin compound synthesis. For example, the processes described herein may be used in the generation of starting materials and intermediate compounds used previously in ecteinascidin compound syntheses. Said starting materials and intermediates can then be used following know processes to arrive at the target ecteinascidin compounds.

The present invention is directed to processes for the synthesis of an ecteinascidin compound, comprising a step of oxidizing a reaction mixture comprising a compound of Formula I to give a compound of Formula II. Further synthetic steps are needed in order to arrive at the final ecteinascidin compound. These further steps will be known to the skilled person. Non-limiting examples of further synthetic steps are outlined below.

The process may comprise further synthetic steps as disclosed in Cragg et al., Anticancer Agents from Natural Products (2012), 2^nd Edition - Chapter 12: “Ecteinascidin-743 (Yondelis®), Aplidin®, and Irvalec®” (pages 291-316); WO 01/87895 A1 (and references contained therein); WO 201 1/147828 A1 (and references contained therein); and WO 2018/197663 A1 (and references contained therein), all of which (and the references contained therein) are incorporated by reference.

Preferably, R3 in Formula I is hydrogen. Exemplary further synthetic steps are provided in the following schemes:

Scheme I wherein R2 is Prot^NHand R3, R4 and Rs are as defined in Scheme I.

Preferably, R2 is selected from allylcarbamate (Alloc), 2,2,2-trichloroethylcarbamate (Troc), benzylcarbamate (Cbz), 9-fluorenylmethyl-carbamate (Fmoc), CONHPh, CSNHPh, and t- butylcarbamate (Boc), more preferably t-butylcarbamate (Boc). Preferably, R3 and R4 are independently selected from methoxyethoxymethyl ether (MEM) and methoxymethyl ether (MOM).

Preferably, Rs is different to R3. More preferably, Rs is allyl.

The protection of the phenol of Formula Ila to give a compound of Formula III is typically carried out by reaction with a suitable reagent for the protection of phenol groups. Preferred reagents for such reaction are alkoxymethyl chlorides, alkoxymethyl bromides and alkoxyalkoxymethyl chlorides. Alkoxyalkoxymethyl chlorides are particularly preferred reagents. Preferred reagents are methoxyethoxymethyl chloride (MEMCI) or methoxymethyl chloride (MOMCI).

The conversion of the methoxyquinone of Formula III to give the hydroxyquinone of formula IV is typically carried out by reaction with a suitable reagent for the deprotection of methoxy groups or by reaction with a hydroxide. Preferred reagents for such reaction are a hydroxide or Nal in presence of a base. More preferably the reaction is carried out with an alkaline hydroxide. The most preferred alkaline hydroxide is NaOH.

The reduction of the hydroxyquinone of Formula IV is typically carried out using a transition metal catalysed hydrogenation or a reducing reagent such as Na2S2C . A transition metal catalysed hydrogenation is particularly preferred. The most preferred transition metal catalyst is Pd I C.

The cyclisation reaction of the compound of Formula V is typically carried out by reaction with a suitable reagent for the protection of 1 ,2-diols as methylene acetals. Preferred reagents include dihalomethane reagents such as dibromomethane, bromochloromethane, dichloromethane and diiodomethane. The most preferred dihalomethane reagent is bromochloromethane.

The protection of the phenol of Formula VI to give a compound of Formula VII is typically carried out by reaction with a suitable reagent for the protection of phenol groups. Preferred reagents for such reaction are allyl halides, for example allyl chloride, allyl bromide and allyl iodide. The most preferred reagent is allyl bromide.

The conversion of the compound of Formula VII to the compound of Formula VIII typically involves deprotection of the amino group on R2. Suitable conditions and reagents for the deprotection of these protecting groups are known to the skilled person (see Wuts, PGM and Greene TWin Protecting Groups in Organic Synthesis, 4^th Ed. Wiley-lnterscience, and Kocienski PJ in Protecting Groups, 3^rd Ed. Georg Thieme Verlag). For example, in the case of t-butyl carbamate, the deprotection is typically conducted using acidic conditions. A preferred reagent is trifluoroacetic acid.

The conversion of the compound of Formula VII to the compound of Formula VIII typically involves deprotection of the phenol group on R3. Suitable conditions and reagents for the deprotection of these protecting groups are known to the skilled person (see Wuts, PGM and Greene TWin Protecting Groups in Organic Synthesis, 4^th Ed. Wiley-lnterscience, and Kocienski PJ in Protecting Groups, 3^rd Ed. Georg Thieme Verlag). For example, in the case of MEM and MOM, the deprotection is typically conducted using acidic conditions. A preferred reagent is trifluoroacetic acid. The conversion of the compound of Formula VII to the compound of Formula VIII typically involves an Edman degradation reaction. Suitable reagents include reaction with an aryl isocyanate or with an arylisothiocyanate. Particularly preferred reagents for such reaction are arylisothiocyanates. The most preferred reagent is phenylisothiocyanate. The degradation may be completed using acidic conditions in a one-pot manner to degrade a thus-generated urea or thiourea. A preferred reagent is hydrogen chloride (e.g. HCI/dioxane).

The optional re-protection of the compound of formula VIII to the compound of formula VII lb is typically carried out by reaction with a suitable reagent for the protection of phenol groups. Preferred reagents for such reaction are alkoxymethyl chlorides, alkoxymethyl bromides and alkoxyalkoxymethyl chlorides. Alkoxyalkoxymethyl chlorides are particularly preferred reagents. Preferred reagents are methoxyethoxymethyl chloride (MEMCI) or methoxymethyl chloride (MOMCI).

The process may further comprises a sequence of steps showed in Scheme II:

Scheme II wherein R4 is Prot^OH, Rs is Prot^OH, Rs is Prot^NH and R7 is Prot^SH, wherein Prot^SH is a protecting group for

SH.

Preferably, R4 is selected from methoxyethoxymethyl ether (MEM) and methoxymethyl ether (MOM).

Preferably, Rs is different to R4. More preferably, Rs is allyl.

Preferably, Rs is selected from allylcarbamate (Alloc), 2,2,2-trichloroethylcarbamate (Troc), benzylcarbamate (Cbz), 9-fluorenylmethyl-carbamate (Fmoc), CONHPh, CSNHPh, and t- butylcarbamate (Boc), more preferably t-butylcarbamate (Boc), more preferably t-butylcarbamate (Boc). Preferably, R7 is selected from substituted or unsubstituted S-9-fluorenylmethyl. More preferably, R7 is S-9-fluorenylmethyl (Fm).

Alternatively, the compound of formula XI can be obtained by the sequence of steps showed in Scheme III:

Scheme III wherein R4 is Prot^OH, Rs is Prot^OH, Rs is Prot^NH, and R7 is Prot^SH.

Preferably, R4 is different to Rs. More preferably, R4 is methoxyethoxymethyl ether (MEM) or methoxymethyl ether (MOM).

Preferably, Rs is different to R4. More preferably, Rs is allyl.

Preferably, Rs is selected from allylcarbamate (Alloc), 2,2,2-trichloroethylcarbamate (Troc), benzylcarbamate (Cbz), 9-fluorenylmethyl-carbamate (Fmoc), CONHPh, CSNHPh, and t- butylcarbamate (Boc), more preferably t-butylcarbamate (Boc), more preferably t-butylcarbamate (Boc).

Preferably, R7 is selected from substituted or unsubstituted S-9-fluorenylmethyl. More preferably, R7 is S-9-fluorenylmethyl (Fm).

In Schemes II and III:

The conversion of the primary amine of formula VIII or Vlllb to provide the primary alcohol of formula IX or Xb is typically carried out by reaction with a suitable oxidizing reagent such as an inorganic nitrite, nitrogen tetroxide or a nitroferricyanide. More preferred oxidizing reagents are inorganic nitrites. Sodium nitrite is the most preferred oxidizing reagent for this step.

The esterification of a compound of Formula IX or Xb to give a compound of Formula Xa or XI is typically carried out by reaction with an amino- and sulphur- protected cysteine amino acid wherein the amino acid is activated by a coupling agent such as a carbodiimide, a phosphonium salt, an uronium salt, a guanidinium salt, an imidazolium derived reagent, or a triazolium derived reagent. Particularly preferred coupling agents are carbodiimides. Most preferred coupling agents are 1 -ethyl-3-(3- dimethylaminopropyl)-carbodiimide (EDC) and its hydrochloride salt (EDC.HCI).

In Scheme II: The protection of the phenol of Formula Xa to give a compound of Formula XI is typically carried out by reaction with suitable reagents for the protection of phenol groups. Preferred reagents for such reaction are alkoxymethyl chlorides, alkoxymethylbromides and alkoxyalkoxymethyl chlorides. Alkoxyalkoxymethyl chlorides are particularly preferred reagents. The most preferred reagent is methoxyethoxymethyl chloride (MEMCI).

The process may further comprises a series of steps showed in Scheme IV:

XVI

Scheme IV wherein R4 and Re are as defined in Scheme IV, Rs is Prot^OH, R7 is Prot^SH and Rs is a -C(=O)R^a group, wherein R^a is selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, and substituted or unsubstituted C2-C12 alkynyl.

Preferably, Rs is different to R4. More preferably, Rs is allyl.

Preferably, Rs is acetyl.

The deprotection of the compound of Formula XI to give the compound of Formula XII involves deprotection of the phenol group on Rs. Suitable conditions and reagents for the deprotection of these protecting groups are known to the skilled person (see Wuts, PGM and Greene TWin Protecting Groups in Organic Synthesis, 4^th Ed. Wiley-lnterscience, and Kocienski PJ in Protecting Groups, 3^rd Ed. Georg Thieme Verlag). For example, in the case of allyl, the deprotection is typically conducted using metal catalysis. Preferred catalysts include palladium(O) catalysts and palladium (II) catalysts in the presence of a reducing reagent, such as a trialkyltin hydride or secondary amines.

The oxidation reaction of a compound of Formula XII to form a compound of Formula XIII is typically effected by reaction with a suitable oxidant, for example with hydrogen peroxide, an organic peroxide, a perbenzoic acid, a periodate, lead tetraacetate, lead oxide, selenium dioxide, hypervalent iodine oxidants such as 2-iodoxybenzoic acid (IBX), or with an organic seleninic anhydride such as (PhSeO)2O. More preferred oxidants are organic seleninic anhydrides and hypervalent iodine oxidants. Organic seleninic anhydrides are even more preferred. The most preferred oxidant is (PhSeO)2O.

The cyclisation reaction of a compound according to Formula XIII to provide a compound of Formula XIV is typically effected by forming an exendo quinone methide at the 4-position of ring B, allowing the methide to react with the sulphur atom of the cysteine residue and capturing the resulting phenoxide with an acylating reagent. Typically, the methide is formed by reaction of the compound of Formula XIII with an in situ-generated Swern reagent (such as by reaction of Tf2O with DMSO) followed by treatment with a base (such as tetramethylguanidine). Typically, the cyclization is carried out by removing the protecting group for SH under conditions that allow the formation of a thiolate ion, followed by nucleophile addition of sulphur to the quinone methide to generate the 10-membered lactone bridge, and the resulting phenoxide is captured using an acylating agent (such as acetic anhydride, a mixed acetyl anhydride, or acetyl chloride) to give the acylated compound of Formula XIV. The conversion of the compounds of Formula XIV or XV-lnt-a to the compound of Formula XV and the conversion of the compound of formula XIV to the compound of Formula XV-lnt-b typically involve deprotection of the amino group on Re. Suitable conditions and reagents for the deprotection of these protecting groups are known to the skilled person (see Wuts, PGM and Greene TWin Protecting Groups in Organic Synthesis, 4^th Ed. Wiley-lnterscience, and Kocienski PJ in Protecting Groups, 3^rd Ed. Georg Thieme Verlag). For example, in the case of t-butyl carbamate, the deprotection is typically conducted using acidic conditions. A preferred reagent is p-toluenesulfonic acid or p-toluenesulfonic acid monohydrate.

The conversion of the compounds of Formula XIV or XV-lnt-b to the compound of Formula XV and the conversion of the compound of formula XIV to the compound of formula XV-lnt-a typically involve deprotection of the phenol group on R4. Suitable conditions and reagents for the deprotection of these protecting groups are known to the skilled person (see Wuts, PGM and Greene TWin Protecting Groups in Organic Synthesis, 4^th Ed. Wiley-lnterscience, and Kocienski PJ in Protecting Groups, 3^rd Ed. Georg Thieme Verlag). For example, in the case of MEM and MOM, the deprotection is typically conducted using acidic conditions. Particular reagents include p-toluenesulfonic acid or p-toluenesulfonic acid monohydrate or HCI (e.g. in EtOAc).

Preferably, the deprotection of the amino group on Re and the deprotection of the phenol group on R4 is conducted in one-pot manner.

The transamination of the compound of Formula XV to provide a compound of Formula XVI is typically conducted using a suitable carbonyl reagent such as a hindered 1 ,2-benzoquinone or a pyridine- or pyridinium carboxaldehyde. More preferred carbonyl reagents are the methiodide of pyridine-4- carboxaldehyde and the methylbenzenesulfonate of pyridine-4-carboxaldehyde.

The process may further comprises a series of steps showed in Scheme V:

Scheme V wherein Rs is a -C(=O)R^a group, wherein R^a is selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, and substituted or unsubstituted C2-C12 alkynyl; and

Xi and X2 are independently selected from hydrogen and unsubstituted or unsubstituted C1-C12 alkyl.

Preferably, Rs is acetyl.

Preferably, Xi is hydrogen. Preferably, X2 is hydrogen.

The conversion of the compound of Formula XVI to provide the compound of Formula XVIIa is typically conducted using a Pictet-Spengler reaction. Typically, the reaction is conducted under acid catalysis. A preferred catalyst is silica gel.

Preferably, the compound of Formula A is: The conversion of the compound of Formula XVIIa to provide the compound of Formula XVIIIa is typically carried out by reaction with a nitrile-coordinating transition metal salt. More preferred salts are salts of Ag(l) or Cu(l). The most preferred salts are AgNCh and CuCI.

Preferably, the compound of Formula XVI Ila is trabectedin:

In another embodiment, the process may further comprises a series of steps showed in Scheme VI:

Scheme VI wherein Rs is a -C(=O)R^a group, wherein R^a is selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, and substituted or unsubstituted C2-C12 alkynyl;

X is -NH- or -O-; Yi is selected from hydrogen, OR^b, OC(=O)R^C, OC(=O)OR^b, OC(=O)NR^dR^e, SR^f, SOR^C, SO₂R^C, C(=O)R^C, C(=O)OR^b, C(=O)NR^dR^e, NO₂, NR^dR^e, N(R^d)C(=O)R^c, N(R^d)-OR^b, C(R^c)=NOR^b, N(R^d)C(=O)OR^b, N(R^d)C(=O)NR^dR^e, CN, halogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alky ny I, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic group;

Y2 and Y3 are independently selected from hydrogen and substituted or unsubstituted C1-C12 alkyl; each R^b is independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alky ny I, substituted or unsubstituted aryl, substituted or unsubstituted heterocyclic group, and a protecting group for OH; each R^c is independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alky ny I, substituted or unsubstituted aryl, and substituted or unsubstituted heterocyclic group; each R^d and R^e is independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alky ny I, substituted or unsubstituted aryl, substituted or unsubstituted heterocyclic group, and a protecting group for amino; and each R^f is independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alky ny I, substituted or unsubstituted aryl, substituted or unsubstituted heterocyclic group, and a protecting group for SH.

Preferably, Rs is as described herein.

Preferably, Y1 is selected from hydrogen and OR^b. In some more preferred embodiments, Y1 is hydrogen. In other more preferred embodiments, Y1 is OR^b, preferably methoxy.

Preferably, Y2 is hydrogen.

Preferably, Y3 is selected from hydrogen, -CH2OH, -CH2OC(=O)R9, -CH2NH2 and -CH2NHR¹¹, wherein Rg is selected from substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, and substituted or unsubstituted C2-C12 alkynyl, and R^h is Prot^NH.

The conversion of the compound of Formula XVI to provide the compound of Formula XVIIb is typically conducted using a Pictet-Spengler reaction. Typically, the reaction is conducted under acid catalysis. A preferred catalyst is silica gel.

The conversion of the compound of Formula XVIIb to provide the compound of Formula XVIIIb is typically carried out by reaction with a nitrile-coordinating transition metal salt. More preferred salts are salts of Ag(l) or Cu(l). The most preferred salts are AgNOs and CuCI.

Possible steps in Scheme VI are showed in Scheme VII:

Scheme VII wherein Rs is a -C(=O)R^a group, wherein R^a is selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, and substituted or unsubstituted C2-C12 alkynyl;

X is -NH- or -O-;

Y1 is hydrogen or a -OR^b group, wherein R^b is selected from substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, and substituted or unsubstituted C2-C12 alkynyl;

Y3 is selected from hydrogen, -CH2OH, -CH2OC(=O)R9, -CH2NH2 and -CH2NHR¹¹, wherein Ra is selected from substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, and substituted or unsubstituted C2-C12 alkynyl, and R^h is Prot^NH.

Preferably, Rs and Y1 are as described herein.

Preferably, Y3 is selected from -CH2NH2 and -CH2NHR¹¹, more preferably -CH2NHR¹¹.

Preferably, R^h is Alloc. Preferably, Y3 is -CH2NHR¹¹, and the process further comprises a step of conducting a deprotection reaction to convert -CH2NHR¹¹ to -CH2NH2, after the step of reacting the compound of Formula XVI with the compound of Formula B to provide the compound of Formula XVIIb. Suitable conditions and reagents for the deprotection of this protecting groups are known to the skilled person (see Wuts, PGM and Greene TW in Protecting Groups in Organic Synthesis, 4^th Ed. Wiley-lnterscience, and Kocienski PJ in Protecting Groups, 3^rd Ed. Georg Thieme Verlag). For example, in the case of Alloc, the deprotection is typically conducted using metal catalysis. Preferred catalysts include palladium(O) catalysts and palladium (II) catalysts in the presence of a reducing reagent, such as a trialkyltin hydride or secondary amines.

Possible steps in Scheme VI are showed in Scheme VIII:

XVIIb-1B X = -O-

Scheme VIII wherein Rs is a -C(=O)R^a group, wherein R^a is selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, and substituted or unsubstituted C2-C12 alkynyl;

Y1 is hydrogen or a -OR^b group, wherein R^b is selected from substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, and substituted or unsubstituted C2-C12 alkynyl; Y3 is selected from hydrogen, -CH2OH and -CH2OC(=O)R9, wherein Ra is selected from substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, and substituted or unsubstituted C2-C12 alkynyl.

Preferably, Rs and Y1 are as described herein.

Preferably, Y3 is selected from hydrogen and -CH2OH. In some more preferred embodiments, Y3 is hydrogen. In other more preferred embodiments, Y3 is -CH2OH.

Preferably, the compound of Formula B is: Preferably, the compound of Formula B is:

Preferably, the compound of Formula B is:

Preferably, the compound of Formula XVIIIb is lurbinectedin:

Preferably, the compound of Formula XVIIIb is ecubectedin:

Preferably, the compound of Formula XVIIIb is:

Preferably, in formula Xa, XI, XII and XIII the stereochemistry at the asymmetric carbon bonded to the NHRe group is (R).

Preferably, in formula XIV, XV, XV-lnt-a, XV-lnt-b the stereochemistry at the asymmetric carbon bonded to the NHRe or NH2 group is (R).

Intermediate compounds

According to a further aspect of the present invention, provided herein are compounds according to Formula I:

I wherein Ri to R3 are as defined herein.

Preferably, the compound is of formula:

HQ-2

Preferably, the compound is of formula:

In an alternative preferred embodiment, the compound according to Formula I does not include Compound HQ-3. According to a further aspect of the present invention, provided herein is a compound of formula:

The present invention is further described in the following non-limiting examples.

EXAMPLES

Isolation Examples 1 to 3: Isolation Example 1 - Compound HQ-1 :

HQ-1

Due to the difficult isolation of HQ-1 without oxidation, HQ-1 was prepared by reduction of 1 , and then compared, by means of HPLC/UV method, with a HQ-1/1 mixture.

Procedure: A vessel containing 25 mg of 1 and 9 mg of 10 % Pd/C in 0.7 mL of CD3OD was bubbled for 5 min. with a hydrogen stream and then the mixture was stirred for 2 h under a hydrogen atmosphere.

The yellow solution turned into a colorless solution. The Pd/C was filtered off under nitrogen atmosphere and the product was immediately analysed by NMR and HPLC/UV/MS technique.

The HPLC/UV and UV data were compared with the HQ-1/1 mixture and proved that the compound was HQ-1 . HPLC method:

Mobile phase A: ammonium acetate 10 nM 1 % DEA adjusted at pH 3.0 with formic acid

Mobile phase B: acetonitrile Column: waters, Symmetry 300 C18 5pm 250 mm x 4.6 mm

Precolumn: Waters, Symmetry C18 5pm 20 mm x 3.9 mm

Oven temperature: 40°C

Injector temperature: 5°C

Detection 268 nm; DAD acquisition

Gradient: at 0 min: 5% of B

From 5% to 13% of B in 17 min

From 13% to 38% of B in 9 min

From 38% to 5% of B in 2 min

And 8 min at 5% of B

Injection volume: 50 pL

Flow rate: 1 .2 mL/min rt of 1 : 12 min (UV max 268 nm); rt of HQ-1 : 10 min (rrt 0.81) (UV max 285 nm)

¹H NMR (400 MHz, CD3OD) 6 6.50 (s, 1 H), 4.55 (dd, J = 5.5, 2.6 Hz, 1 H), 4.17 (d, J = 2.6 Hz, 1 H), 4.13 - 4.08 (m, 1 H), 3.72 (s, 3H), 3.64 (s, 3H), 3.49 - 3.39 (m, 2H), 3.34 - 3.32 (m, 1 H), 3.26 - 3.17 (m, 1 H), 3.08 (dd, J = 13.2, 5.5 Hz, 1 H), 3.05 - 2.94 (m, 1 H), 2.73 (q, J = 6.9 Hz, 1 H), 2.56 - 2.48 (m, 1 H), 2.26 - 2.22 (m, 6H), 2.10 (s, 3H), 1.82 (dd, J = 15.8, 12.3 Hz, 1 H), 0.94 (d, J = 6.9 Hz, 3H).

¹³C NMR (101 MHz, CD3OD) 6 176.30, 147.58, 143.99, 139.74, 130.84, 129.23, 120.63, 120.32, 120.24, 117.63, 93.52, 59.42, 59.36, 56.54, 53.18, 53.09, 52.84, 50.14, 42.41 , 40.11 , 25.86, 24.54, 19.82, 14.56, 8.37.

ESI m/z 525.5 [M-H₂O+H] ⁺

UV max: 285 nm

Isolation Example 1 - Compound HQ-2:

HQ-2

Due to the difficult isolation of HQ-2 without oxidation, HQ-2 was prepared by reduction of 2, and then compared, by means of HPLC/UV method, with a HQ-2/2 mixture prepared from HQ-1/1 mixture subjected to cyanation.

Procedure: A vessel containing 15 mg of 2 and 5 mg of 10 % Pd/C in 0.5 mL of CD3OD was bubbled for 5 min. with a hydrogen stream and then the mixture was stirred for 2 h under a hydrogen atmosphere. The yellow solution turned into a colorless solution. The Pd/C was filtered off under nitrogen atmosphere and the product was immediately analysed by NMR and HPLC/UV/MS technique.

The HPLC/UV and UV data were compared with the cyanated HQ-1/1 mixture and proved that the compound was HQ-2.

HQ-2 is detected by HPLC/UV/MS technique:

HPLC method:

Mobile phase B: acetonitrile

Column: waters, Symmetry 300 C18 5pm 250 mm x 4.6 mm

Precolumn: Waters, Symmetry C18 5pm 20 mm x 3.9 mm

Oven temperature: 40°C

Injector temperature: 4°C

Detection 268 nm; DAD acquisition

Gradient: at 0 min: 5% of B

From 5% to 50% of B in 60 min

From 50% to 5% of B in 2 min

And 10 min at 5% of B

Injection volume: 10 pL Flow rate: 1 .2 mL/min rt of 2: 22 min (UV max 268 nm); n of HQ-2: 11 .6 min (UV max 285 nm)

¹H NMR (400 MHz, CD3OD) 6 6.48 (s, 1 H), 4.32 (d, J = 2.5 Hz, 1 H), 4.16 (d, J = 3.0 Hz, 2H), 3.72 (d, J = 0.8 Hz, 3H), 3.65 (d, J = 0.8 Hz, 3H), 3.64 - 3.57 (m, 2H), 3.43 - 3.23 (m, 2H), 3.15 - 2.97 (m, 2H), 2.79 - 2.69 (m, 1 H), 2.69 - 2.59 (m, 1 H), 2.30 - 2.18 (m, 6H), 2.12 (s, 3H), 1 .89 (dd, J = 16.1 , 11 .9 Hz, 1 H), 0.88 (dd, J = 7.0, 0.8 Hz, 3H).

¹³C NMR (101 MHz, CD3OD) 5 176.20, 147.66, 144.08, 143.45, 139.82, 130.94, 129.22, 120.41 , 120.09, 118.43, 117.98, 117.79, 59.55, 59.48, 59.37, 56.70, 56.58, 56.56, 55.29, 50.01 , 40.76, 40.45, 25.79, 25.08, 19.66, 14.53, 8.41.

ESI m/z 525.5 [M-CN+H] ⁺ 552.5 [M+H] ⁺

UV max: 285 nm

Isolation Example 1 - Compound HQ-3:

Procedure A: From a crude mixture of HQ-3/3 obtained from a HQ-1/1 mixture subjected to cyanation reaction followed by introduction of the tert-butoxycarbonyl group (see reactions below), HQ-3 was isolated by evaporating to dryness the aqueous phase.

The NMR, UV, HPLC/MS data match the data of the compound obtained by reducing compound 3 as follows, which confirms its structure.

Procedure B: A vessel containing 15 mg of 3 and 2 mg of 10 % Pd/C in 0.7 mL of CD3OD was bubbled for 5 min. with a hydrogen stream and then the mixture was stirred for 2 h under a hydrogen atmosphere. The yellow solution turned into a colorless solution. The Pd/C was filtered off under nitrogen atmosphere and the product was immediately analysed by NMR and HPLC/UV/MS technique.

HPLC method:

Precolumn: Waters, Symmetry C18 5pm 20 mm x 3.9 mm

Oven temperature: 40°C

Detection 268 nm; DAD acquisition

Gradient: at 0 min: 5% of B

From 5% to 35% of B in 30 min

From 35% to 60% of B in 50 min

From 60% to 5% of B in 2 min

And 8 min at 5% of B

Injection volume: 10 pL

Flow rate: 1 .2 mL/min rt of 3: 42.38 min (UV max 268 nm); rt of HQ-3: 29.8 min (UV max 285 nm)

Characterisation data:

¹H NMR (400 MHz, CD3OD) 6 6.48 (s, 1 H), 4.31 (d, J = 2.5 Hz, 1 H), 4.19 - 4.12 (m, 2H), 3.71 (d, J = 0.7 Hz, 3H), 3.66 (d, J = 0.7 Hz, 3H), 3.43 (d, J = 6.3 Hz, 1 H), 3.38 - 3.19 (m, 3H), 3.11 - 2.95 (m, 2H), 2.71 - 2.58 (m, 1 H), 2.29 - 2.19 (m, 6H), 2.11 (s, 3H), 1.95 (t, J = 14.1 Hz, 1 H), 1.35 (s, 9H), 0.92 (d, J = 7.1 Hz, 3H).

¹³C NMR (101 MHz, CD3OD) 5 173.46, 155.80, 147.61 , 144.07, 143.63, 143.57, 139.66, 130.84, 129.17, 120.64, 120.1 1 , 1 18.59, 1 18.02, 117.92, 1 17.71 , 79.05, 59.89, 59.48, 59.32, 57.08, 56.73, 56.61 , 55.38, 49.69, 41.92, 40.42, 27.23, 25.75, 25.15, 17.04, 14.64, 8.43.

ESI m/z 625.6 [M-CN+H]⁺ 652.5 [M+H]⁺

UV max: 285 nm

Examples 1 to 5 - Oxidation of compound HQ-1 to compound 1 : effect of different oxidants

Starting materials:

For Examples 1 to 4, a broth from Pseudomonas fluorescens was used (produced according to

JPS59225189A). The starting material pH solution was 6.26. The compound HQ-1 compound 1 ratio was:

For Example 5, a 50 mL aliquot of methanolic concentrate with the following composition was used:

Compound HQ-1 : 59.8% (in HPLC area)

Compound 1 : 40.1 % (in HPLC area)

The methanolic concentrate was obtained using the following process. To the fermentation broth, a SepaBeads 825L or 850 resin was added to adsorb compound HQ-1 and compound 1 . Then the resin was filtered off and the HQ-1 and 1 compounds were desorbed with methanol or with a 0.1 to 1 % of formic acid methanol solution. The solvent was evaporated to a 3-5 g/L concentration of (HQ-1 + 1).

Procedure:

Examples 1 to 4: An air stream was bubbled through a 100 mL of solution at 22 °C, at the indicated pH, for 10 min. To this mixture, under air atmosphere, the oxidant was added. Oxidant equivalents were calculated based on the amount of compound HQ-1.

Samples were withdrawn and analysed at different times to check reaction progress.

Contents of compound HQ-1 and compound 1 were determined by HPLC.

Example 5: An air stream was bubbled through the 50 mL aliquot of methanolic concentrate at 22 °C, at the indicated pH, for 10 min or throughout during the course of the experiment. To this mixture, under air atmosphere, the oxidant 1 ,4-benzoquinone was added. Oxidant equivalents were calculated based on the amount of compound HQ-1 . Samples were withdrawn and analysed at different times to check reaction progress.

Contents of compound HQ-1 and compound 1 were determined by HPLC area. The compound HQ- 1/compound 1 ratio was calculated taking into account the compound 1/ compound HQ-1 relative response factor is 4.5 at 268 nm. A lower number for the compound HQ-1/compound 1 ratio indicates a higher conversion of starting material to oxidized product.

HPLC method:

Mobile phase A: ammonium acetate 10 nM 1% DEA adjusted at pH 3.0 with formic acid

Mobile phase B: acetonitrile

Column: waters, Symmetry 300 C18 5pm 250 mm x 4.6 mm

Precolumn: Waters, Symmetry C18 5pm 20 mm x 3.9 mm

Oven temperature: 40°C

Injector temperature: 5°C

Detection 268 nm

Gradient: at 0 min: 5% of B

From 5% to 13% of B in 17 min

From 13% to 38% of B in 9 min

From 38% to 5% of B in 2 min

And 8 min at 5% of B rt of 1 : 12 min approx, rt of HQ-1 : 10 min approx.

Experiment parameters:

Results:

Examples 1 to 5 indicate that various oxidizing agents can be used to oxidize compound HQ-1 to compound 1 , including air, H2O2, 1 ,4-benzoquinone, CuSC and FeCh.

In particular, in the experiments using CuSC as oxidant, these were carried out at two different pH conditions: 4.15 and 7.22. At pH 7.22, compound HQ-1 was completely oxidized. CuSC also proved to be an effective oxidant at low pH after 2h, and in addition no degradation of compound 1 was observed over time.

Similar results were obtained with FeCh, which also oxidized efficiently at acidic pH. In this case, compound 1 was also stable after 5h.

Neither FeCh nor CuSCU showed a reversible behaviour over time.

Overall, various oxidizing agents can be used to oxidize compound HQ-1 to compound 1. FeCh and CuSO4 were especially suitable, since both are water soluble and allow oxidation at acidic pH, where the products are more stable.

Examples 6 to 10 - Oxidation of compound HQ-1 to compound 1 : effect of atmosphere and water dilution

Starting materials:

Solution 1

A methanolic concentrate was used, prepared as mentioned for Example 5. The starting material pH solution was 4.48. The compound HQ-1 compound 1 ratio was:

Solution 2 A methanolic concentrate was used, prepared as mentioned for Example 5. The starting material pH solution was 4.26. The compound HQ-1 compound 1 ratio was:

Procedure:

An air stream was bubbled through a 100 mL sample of methanolic concentrate at 22 °C for 10 min. To this mixture, under air atmosphere, the oxidant was added. Oxidant equivalents were calculated based on the amount of compound HQ-1 , or the compound HQ-1 and compound 1 amount.

To carry on the experiment under nitrogen atmosphere, a vacuum was applied to the solution to remove oxygen and then a nitrogen stream was bubbled instead through the methanolic solution for 10 min.

In Example 8, the methanolic concentrate after inertization was diluted with water (166 mL per 100 mL of methanolic concentrate), followed by the addition of oxidant.

In Example 10-2, the methanolic concentrate of after oxidation of Example 10-1 was diluted with water (166 mL per 100 mL of methanolic concentrate).

Contents of compound HQ-1 and compound 1 were determined by HPLC.

Experiment parameters: *the oxidant equivalents were calculated based on the compound HQ-1 amount.

** the oxidant equivalents were calculated based on the compound HQ-1 and compound 1 amount.

Results:

*the time represents after dilution of the product of Example 10-1 with water.

Examples 6 and 7 clearly show the capability of FeCh to oxidize compound HQ-1 to compound 1 in either inert or oxygenated atmospheres, at acidic pH. It should be noted that the amount of compound 1 was identical even after 5h.

Example 8 shows that the oxidation still proceeded smoothly under dilution conditions, although a small amount of incomplete oxidation was observed.

Example 9 shows that CuSC resulted in the oxidation of compound HQ-1 in an inert atmosphere, at acidic pH. A small amount of incomplete oxidation was observed. Example 10 shows complete transformation in 30 min, likely due to the higher oxidant equivalents added compared to Example 6, and also likely due to the higher concentration compared to Example 8.

Overall, FeCh has the highest oxidant effect among the tested oxidants in an inert atmosphere. This allows the oxidation to be conducted in the absence of oxygen, an advantage relating with security requirements. Only 3 equivalents of FeCh were required to achieve total compound HQ-1 oxidation in 30 min. In addition, it was confirmed that CuSO4 could be used as oxidant, whilst oxidation still proceeded under dilution conditions.

Example 1 1 - Oxidation of compound HQ-1 to compound 1 : effect of temperature

Starting materials: A methanolic concentrate was used, prepared as mentioned for Example 5. The starting material pH solution was 4.26. The compound HQ-1 compound 1 ratio was:

Procedure:

To 50 mL of a methanolic solution containing compound HQ-1 and compound 1 was added 83 mL of water. The pH was adjusted to 4.05 with a 10% H2SO4 solution and the mixture was thermostated at 15.5 °C.

A nitrogen stream was bubbled throughout the solution for 5 min to remove oxygen traces. At this moment, 26% FeCh.6H2O (500 mg in 1.9 mL of H2O, 3 eq. with respect to compound HQ-1 and compound 1 amount) was added. The solution turned green.

Contents of compound HQ-1 and compound 1 were determined by HPLC.

Results:

Example 11 shows that the oxidation at lower temperature is comparable to the procedure at 22 °C (Example 8).

Example 12 - Oxidation of compound HQ-1 to compound 1 : effect of FeCh equivalents

Starting materials:

A methanolic concentrate was used, prepared as mentioned for Example 5. The starting material pH solution was 4.26. The compound HQ-1 compound 1 ratio was:

Procedure:

Using the same procedure as Example 11 , the number of equivalents of FeCh (with respect to compound HQ-1 and compound 1 amount) was decreased from 3 to 1 .5.

Contents of compound HQ-1 and compound 1 were determined by HPLC.

Results:

Example 12 shows that the oxidation at lower equivalents is possible, albeit at slightly poorer conversion than compared to the procedure using 3 equivalents of FeCh (Example 11).

Example 13 - Oxidation of compound HQ-1 to compound 1 : effect of visible light

Procedure:

The experiments were conducted on a 50 mL aliquot of methanolic concentrate, prepared as mentioned for Example 5, with the following composition:

Compound HQ-1 : 59.8% (in HPLC area)

Compound 1 : 40.1 % (in HPLC area)

A series of reactions were run at room temperature, in which the pH was adjusted to 3.8, where the atmosphere was a nitrogen or air atmosphere, and where the reactions were conducted in the presence or absence of visible light. Some reactions were conducted on the methanolic concentrate, whereas some reactions were conducted with a diluted methanolic solution.

For diluted samples, the above aliquot was diluted with 125 mL of water.

To evaluate the visible light effect, glass vessels were used for the presence of visible light, and amber glass vessels were used for the absence of visible light.

The reaction progress was evaluated by HPLC analysis at t = 2-5h and then at t = 20-24h.

The compound HQ-1/compound 1 ratio was calculated taking into account the compound 1/ compound HQ-1 relative response factor is 4.5 at 268 nm.

Results:

Example 13 shows that oxidation proceeds under irradiation with visible light and/or under an air atmosphere. The reaction is accelerated if the oxidation is conducted with both the presence of visible light and air atmosphere.

Rate of oxidation was not significantly affected by dilution.

Example 14 - Oxidation of compound HQ-1 to compound 1 : effect of bubbling during reaction

Procedure:

The experiments were conducted on a 50 mL aliguot of methanolic concentrate, prepared as mentioned for Example 5, with the following composition:

Compound HQ-1 : 59.8% (in HPLC area)

Compound 1 : 40.1 % (in HPLC area)

For diluted samples, the above aliguot was diluted with 125 mL of water, then the methanol was partially evaporated to 7.9% of methanol. The compound HQ-1 and compound 1 percentages were measured:

Without dilution With agueous dilution

Compound HQ-1 : 53% (in HPLC area) 57.8% (in HPLC area)

Compound 1 : 47% (in HPLC area) 42.2% (in HPLC area)

The experiments were run at pH 4, or pH 7 by basifying with 10% NaOH.

The air atmosphere was provided using an air balloon. Where bubbling was conducted, this was performed bubbling an air stream throughout the solution during the course of the experiment.

Results: Met. Ext. + H₂Q | Air bubbling | 7 | 3 | 1 .75 | 98.25 | 0.08

Example 14 shows that oxidation proceeds under an air atmosphere, either at acidic or neutral pH. Oxidation at pH 7 proceeded more quickly. In addition, bubbling of air through the reaction solution led to increased oxidation.

Examples 15 to 17 - One-pot cyanation of compound 1 to form compound 2

Starting materials:

Procedure:

To a determined volume of methanolic concentrate, cooled water was added (1.66 mL of water per 1 mL of concentrate). The pH was adjusted to 4-4.2 with 10% H2SO4 or 10% NaOH, as necessary. The mixture was kept at 15 °C and stirred under nitrogen atmosphere. Then a 26% FeCh.6H2O solution was added and a sample for analysis was withdrawn at 30 min and 60 min.

1 to 1.5 hours after the oxidant addition, a KCN aqueous solution (31 g/L) was added at the same temperature.

Samples were withdrawn from the reaction vessel continuously for compound 1 and compound 2 measurement by HPLC.

FeCh.6H2O and KCN equivalents were varied as shown below:

Results:

Addition of KCN proceeded with color change. The green dark color suggested the generation of K4[Fe(CN)e] (blue) and K3[Fe(CN)e] (yellow) complexes.

In Examples 15 and 16, where the cyanide availability was higher, compound 2 was easily obtained within 3 to 4 hours.

In Example 17, the mixture was allowed to react overnight and after 20 hours all compound 1 was converted quantitatively to compound 2.

Overall, Examples 15 to 17 demonstrate that the oxidation of compound HQ-1 to form compound 1 , and subsequent cyanation of compound 1 to form compound 2, is possible using a one-pot process.

Examples 18 to 20 - Boc protection of compound 2 to form compound 3

Procedure:

The solution of compound 2 obtained from Examples 16 to 18 was washed twice with MTBE (50 mL of MTBE per 134 mL of aqueous phase). At 15 °C, the pH was adjusted to 8.3 with 10% NaOH. The cooling bath was removed, and B0C2O (4 eq.) in MTBE (1 g/100 mL) and catalytic DMAP were added.

After the reaction was finished, the phases were decanted and the organic phase was washed twice with water (50 mL of water per 134 mL of solution of compound 2). The organic solvent was evaporated to dryness and the crude was purified by flash chromatography on silica gel (DCM/dioxane). The fraction containing compound 3 was evaporated to dryness, dissolved in toluene (4 mL/g) and poured into heptane (38 mL/g) at 0 °C. The resulted solid was filtered off to afford pure compound 3. Results:

Examples 18 to 20 delivered similar results in terms of chromatographic purity after reaction overnight.

Example 21 - Oxidation of compound HQ-2 to compound 2: effect of pH on oxidation with air

HQ-2 2

Procedure:

An aqueous solution of compound HQ-2 + compound 2 was obtained from 50 mL of a methanolic concentrate with the following composition:

Compound HQ-1 : 59.8% (in HPLC area)

Compound 1 : 40.1 % (in HPLC area) and 125 mL of water, acidified to pH 3.8 and subjected to a cyanation reaction with 13.2 equivalents of

KCN.

Upon termination of the reaction, the pH was adjusted to 4.0 or 7.0 using 10% H2SO4 or 10% NaOH as appropriate and a nitrogen stream was bubbled throughout the mixture to remove oxygen. The aqueous phase was washed twice with MTBE (2x120 mL). This aqueous phase was used as the starting material for the subsequent experiments.

The experiments were carried out at room temperature. Samples were withdrawn to analyse reaction progress.

Results:

Example 21 shows that oxidation proceeds under an air atmosphere, either at acidic or neutral pH. Oxidation at pH 7 proceeded more quickly. In addition, bubbling of air through the reaction solution led to increased oxidation. Example 22 - Oxidation of compound HQ-2 to compound 2: effect of temperature on oxidation with air

Procedure:

The same starting material as Example 21 at pH 7 was used. Air was introduced by means of an air stream during the course of the reaction at 10 °C.

Results:

Example 22 shows that oxidation is able to proceed at 10 °C.

Example 23 - Oxidation of compound HQ-1 and subsequent reactions to form urea derivatives

Step A: Procedure: A methanolic extract containing compound HQ-1 and compound 1 (containing 41 % area of HQ-1) (550 mL, 2.06 g, 3.81 mmol; concentration of HQ-1+1 : 3.74 g/L) was diluted with H2O (650 mL) at 15°C until a concentration of 1.7 g/L was obtained. An aqueous solution of FeCh ■ 6H2O (1.60 g; 5.55 mmol in 5 mL of H2O) was added and stirred for 45 minutes. KCN (2.30 g; 34.29 mmol) in H2O (75 mL) was added and the pH adjusted with 10% aqueous H2SO4 (10 mL) until pH 3.92. The mixture was stirred at 15°C for 3 hours, cooled to 0°C and 3M NaOH (21 mL) was added until pH 8.10.

MTBE (300 mL) and Phenylisocyanate (1.53 mL; 14.1 mmol) were added to the aqueous mixture and warmed to 22°C. After 2 h, the solids were filtered over celite and the celite was washed with MTBE (200 mL). Phases were separated and the aqueous layer extracted with MTBE (100 mL). The combined organic phases were washed with H2O (400 mL), dried over Na2SC>4, filtered and evaporated. Purification by column chromatography (SiC>2, Hexane-AcOEt 0^-65%) yielded the desired compound as an orange solid (1.012 g, 90%).

Rf: 0.42 (Hexane-AcOEt 1 :3)

¹H NMR (400 MHz, CD3OD) 6 7.22 (d, J = 4.2 Hz, 4H), 6.93 (m, 1 H), 6.52 (s, 1 H), 6.04 (bs, 1 H), 5.49 (s, 1 H), 4.43 (d, J = 2.6 Hz, 1 H), 4.22 - 4.16 (m, 1 H), 3.92 (s, 3H), 3.84 (bs, 1 H), 3.65 (s, 3H), 3.68 - 3.57 (m, 1 H), 3.42 - 3.33 (m, 3H), 3.29 - 3.22 (m, 1 H), 3.17 - 3.00 (m, 3H), 2.67 (d, J = 18.3 Hz, 1 H), 2.30 (s, 3H), 2.23 (s, 3H), 2.05 - 1 .92 (m, 1 H), 1 .72 (s, 3H), 0.93 (d, J = 7.1 Hz, 3H).

¹³C NMR (101 MHz, CD3OD) 6 185.6, 181.3, 174.3, 174.2, 155.7, 155.2, 148.0, 143.8, 142.7, 139.5, 134.9, 130.9, 129.7, 128.4, 127.8, 121.7, 119.7, 118.1 , 117.5, 117.4, 59.8, 59.1 , 58.3, 56.01 , 56.0, 55.2, 54.8, 49.3, 40.5, 40.0, 39.9, 24.8, 24.4, 17.5, 14.6, 7.3.

ESI-MS m/z: Calcd. for C36H40N6O7: 668.30. Found (M+H)⁺: 669.30

Step B:

4 5

Procedure: To a solution of compound 4 (18.0 g, 26.92 mmol) in THF (261 mL), cooled to -3°C under nitrogen atmosphere, MOMBr 90% (3.91 mL, 43.07 mmol) and H2O (0.270 mL) were added. Then, NaH 60% (0.18 g; 1 .29 g; 32.30 mmol) was added in portions over a period of 40 minutes and the mixture was stirred for an additional 30 minutes at 0°C. The reaction was quenched with a saturated NH4CI solution (200 mL) and diluted with DCM (100 mL). Phases were separated and the aqueous phase was extracted with more DCM (2 x 50 mL). The combined organic phases were dried over Na2SC>4 and concentrated in vacuo. The residue was purified by column chromatography (SiC>2, DCM:AcOEt 0^70%) to obtain compound 5 (16.0 g, 84%) as an orange solid.

Rf: 0.33 (hexane:AcOEt 1 :3).

¹H NMR (400 MHz, CD3OD) 6 7.21 (m, 5H), 6.98 - 6.88 (m, 1 H), 6.80 (s, 1 H), 5.18 (d, J = 6.1 Hz, 1 H), 5.11 (d, J = 6.1 Hz, 1 H), 4.44 (d, J = 2.6 Hz, 1 H), 4.28 - 4.23 (m, 1 H), 3.91 (s, 3H), 3.82 (bs, 1 H), 3.68 (s, 3H), 3.60 - 3.51 (m, 4H), 3.51 - 3.38 (m, 2H), 3.14 - 3.00 (m, 3H), 2.73 (d, J = 18.0 Hz, 1 H), 2.32 (s, 3H), 2.22 (s, 3H), 1 .98 - 1 .79 (m, 1 H), 1 .69 (s, 3H), 0.92 (d, J = 6.0 Hz, 3H).

¹³C NMR (101 MHz, CD3OD) 6 187.0, 182.8, 175.5, 157.1 , 156.4, 150.4, 149.7, 144.0, 141.0, 136.3,

132.5, 132.2, 129.8, 129.2, 126.0, 125.1 , 123.0, 119.4, 118.8, 100.4, 61 .2, 60.3, 59.7, 58.1 , 57.9, 57.7,

56.5, 56.1 , 50.7, 41.9, 40.8, 26.0, 25.8, 20.9, 18.8, 16.0, 14.5, 8.7.

ESI-MS m/z: Calcd. for C38H44N_eO₈ 712.32. Found (M+H)⁺: 713.32 reaction to form thiourea derivative

Procedure: A methanolic extract containing compound HQ-1 and compound 1 (containing 3% area of HQ-1) (750 mL, 3.30 g, 6.10 mmol; concentration of HQ-1+1 : 4.4 g/L) was diluted with H2O (1 190 mL) at 15°C until a dilution of 1 .7 g/L was obtained. An aqueous solution of FeCh ■ 6H2O (1 .32 g; 6.10 mmol in 4 mL of H2O) was added and stirred for 70 minutes. NaCN (2.69 g; 54.9 mmol) in H2O (11 mL) was added and the pH adjusted with 10% aqueous H2SO4 (10 mL) until pH 3.91 . The mixture was stirred at 15°C for 3 hours, cooled to 0°C and 3M NaOH (21 mL) was added until pH 8.1 .

MTBE (472 mL) and Phenylisothiocyanate (2.70 mL; 22.6 mmol) were added to the aqueous mixture, heated to 22°C and stirred for 18h. The solids were filtered over celite and the celite was washed with MTBE (200 mL). Phases were separated and the aqueous layer extracted with MTBE (200 mL). The combined organic phases were dried over Na2SC>4, filtered and evaporated and the residue was purified by column chromatography (SiC>2, DCM:MeOH 0^-3%) to give compound 6 as an orange solid (3.35 g, 82%).

Rf: 0.41 (DCM-MeOH 96:4).

¹H NMR (400 MHz, CD3OD) 6 7.41 - 7.30 (m, 5H), 7.19 (m, 1 H), 6.25 (s, 1 H), 4.43 (d, J = 2.6 Hz, 2H), 4.22 - 4.12 (m, 2H), 3.93 (s, 3H), 3.86 - 3.77 (m, 1 H), 3.67 (s, 3H), 3.63 - 3.47 (m, 2H), 3.38 (d, J = 7.7 Hz, 2H), 3.12 - 3.03 (m, 2H), 3.02 - 2.91 (m, 1 H), 2.68 (d, J = 18.0 Hz, 1 H), 2.26 (s, 3H), 2.14 (s, 3H), 1 .97 - 1 .84 (m, 1 H), 1 .83 (s, 3H), 0.90 (d, J = 6.0 Hz, 3H).

¹³C NMR (126 MHz, CD3OD) 6 187.2, 182.7, 181.4, 174.3, 157.1 , 149.3, 145.0, 144.2, 139.6, 136.6, 132.3, 131.0, 130.2, 129.4, 126.6, 125.0, 121.1 , 118.9, 118.4, 61.3, 60.9, 59.7, 58.0, 57.3, 56.5, 56.3, 54.8, 54.4, 41.9, 40.7, 30.7, 26.1 , 26.0, 18.7, 16.0, 8.9.

ESI-MS m/z: Calcd. for CseH^NeOeS: 684.27. Found (M+H)⁺: 685.30

Example 25

A fermentation broth was obtained according Examples 1-4.

Procedure: to 10 mL of the fermentation broth, at 22°C and pH 4, the oxidant was added under a nitrogen atmosphere. A sample was withdrawn at different times to analyse by HPLC the reaction progress. The HQ-1+1 content was determined to verify the absence of degradation.

All of the reagents tested demonstrated effectiveness, without degrading HQ-1 or 1 . It can be seen with potassium permanganate that degradation was avoided by using a lower molar equivalent.

Example 26 A methanloic concentrate was obtained according Examples 1-4. Procedure: 10 mL of the methanolic concentrate was diluted with 11.7 mL of water, under a nitrogen atmosphere, to obtain a final concentration of HQ-1+1 in the range of 1.58-1.8 g/L approximately. To this solution, the oxidant was added. The reagent equivalent are calculated based on the total amount of HQ-1+1 , at 22°C and pH 4, the oxidant was added under a nitrogen atmosphere. A sample was withdrawn at different times to analyse by HPLC the reaction progress. The HQ-1+1 content was determined to verify the absence of degradation.

*after 2h with copper sulfate, an oxygen stream was bubbled for 5 minutes into the solution. Then, the mixture was maintained 1 ,5h under an air atmosphere.

In this example, mixtures of oxidants were tested to accelerate oxidation. In all cases, HQ-1 was oxidated effectively with no degradation observed. In summary, the examples show that various oxidants (for example, air (comprising molecular oxygen), H2O2, 1 ,4-benzoquinone, CuSO4, FeCh, chloranil, K3[Fe(CN)e], MnO2, 12, KMnO4, HIO3, and Mn(OAc)3, with FeCh being especially preferred) may be used to convert a compound of Formula I (for example, compound HQ-1 and HQ-2) to a compound of Formula II. A one-pot process for combined oxidation and cyanation has also been demonstrated. Compound HQ-3 has been found to be highly insoluble in both organic and aqueous media, forming precipitates and causing reductions in overall process yield. These examples illustrate that by reducing the amounts of compound HQ-3 produced as a downstream intermediate, for example by oxidizing compounds HQ-1 and/or compound HQ-2 at an earlier stage, or potentially by directly oxidizing compound HQ-3, a reduction in the amount of precipitate produced during the reaction process can be obtained. This thereby leads to a more efficient and higher yielding process, particularly at the plant scale.

Claims

1 . A process forthe synthesis of an ecteinascidin compound, comprising a step of oxidizing a reaction mixture comprising a compound of Formula I to give a compound of Formula II: wherein:

Ri is OH or CN;

R2 is hydrogen or Prot^NH; and

2. A process according to claim 1 , wherein R1 is OH.

3. A process according to claim 1 , wherein R1 is CN.

4. A process according to any one of claims 1 to 3, wherein R2 is hydrogen.

5. A process according to any one of claims 1 to 3, wherein R2 is Prot^NH.

6. A process according to claim 5, wherein Prot^NH is selected from allylcarbamate (Alloc), 2,2,2- trichloroethylcarbamate (Troc), benzylcarbamate (Cbz), 9-fluorenylmethyl-carbamate (Fmoc), CONHPh, CSNHPh, and t-butylcarbamate (Boc), preferably t-butylcarbamate (Boc).

7. A process according to any one of claims 1 to 6, wherein R3 is hydrogen.

8. A process according to any one of claims 1 to 7, wherein oxidation is conducted using an oxidizing agent, biochemical oxidation or electrochemical oxidation.

9. A process according to claim 8, wherein the oxidizing agent is selected from the group consisting of: metal oxidizing agents (such as Cr(VI) compounds, Mn(IV) compounds, Mn(VII) compounds, Fe(lll) compounds, Cu(ll) compounds, Ag(l) compounds, Pb(IV) compounds, Ce(IV) compounds Mn(lll) compounds, Mn(IV) compounds, Mn(VII) compounds), halogen compounds (such as h and HIO3), quinones (such as chloranil), molecular oxygen, hydrogen peroxide, hypochlorite salts (such as NaOCI and Ca(OCI)2), chlorite salts, 1 ,4-benzoquinone and 2,3-dichloro-5,6-dicyano-1 ,4- benzoquinone, or a combination thereof.

10. A process according to claim 9, wherein the oxidizing agent is selected from molecular oxygen, hydrogen peroxide, 1 ,4-benzoquinone and a metal oxidizing agent, or a combination thereof.

11. A process according to claim 9 or claim 10, wherein the metal oxidizing agent is a transition metal oxidizing agent.

12. A process according to claim 11 , wherein the transition metal is Fe, Cu or Mn.

13. A process according to claim 1 1 , wherein the transition metal oxidizing agent is selected from Fe(lll) compounds (e.g. FeCh, or K3[Fe(CN)e]), Cu(ll) compounds (e.g. CuSCU), Mn (III) compounds (e.g. Mn(OAc)3), Mn(IV) compounds (e.g. MnC>2), and Mn(VII) compounds (e.g. KMnC ).

14. A process according to claim 13, wherein the Fe(lll) compound is FeCh.

15. A process according to claim 9, wherein the oxidizing agent is a halogen compound (such as I2 and HIO3).

16. A process according to claim 9, wherein the oxidizing agent is a quinone (such as chloranil).

17. A process according to any one of claims 8 to 16, wherein a number of equivalents of the oxidizing agent with respect to the compound of Formula I in the reaction mixture is about 1 .0 equiv. to about 15.0 equiv., preferably about 1.2 equiv. to about 10.0 equiv., more preferably about 1.5 equiv. to about 8.0 equiv., even more preferably about 2.0 equiv. to about 5.0 equiv.

18. A process according to any one of claims 8 to 10, wherein the oxidizing agent is molecular oxygen.

19. A process according to claim 18, wherein the molecular oxygen is provided by exposing the reaction mixture to a reaction atmosphere comprising molecular oxygen.

20. A process according to claim 18 or claim 19, wherein a stream comprising molecular oxygen is bubbled through the reaction mixture during the step of oxidizing the reaction mixture comprising the compound of Formula I to give the compound of Formula II.

21. A process according to any one of claims 1 to 20, wherein the reaction is conducted at a pH of about 3.0 to about 9.0, preferably about 3.5 to about 8.5, more preferably about 4.0 to about 8.0.

22. A process according to claim 8, wherein the biochemical oxidation is catalysed by hydroquinone oxidase or cells exhibiting hydroquinone oxidase activity.

23. A process according to any one of claims 1 to 22, wherein the reaction mixture further comprises a compound according to Formula II; preferably wherein R1 in the compound according to Formula I in the reaction mixture is the same as R1 in the compound according to Formula II in the reaction mixture, and/or wherein R2 in the compound according to Formula I in the reaction mixture is the same as R2 in the compound according to Formula II in the reaction mixture, and/or wherein R3 in the compound according to Formula I in the reaction mixture is the same as R3 in the compound according to Formula II in the reaction mixture; more preferably wherein R1, R2 and R3 in the compound according to Formula I in the reaction mixture are the same as R1, R2 and R3 in the compound according to Formula II in the reaction mixture.

24. A process according to any one of claims 1 to 23, wherein the step of oxidizing the reaction mixture comprising the compound of Formula I to give the compound of Formula II is conducted at about 0 °C to about 100 °C, preferably about 0 °C to about 80 °C, more preferably about 5 °C to about 60 °C, even more preferably about 5 °C to about 40 °C, yet even more preferably about 10 °C to about 30 °C, most preferably about 10 °C to about 25 °C.

25. A process according to any one of claims 1 to 24, wherein the reaction mixture is a fermentation broth.

26. A process according to any one of claims 1 to 24, wherein the reaction mixture is an extract from a fermentation broth.

27. A process according to any one of claims 1 to 26, further comprising a step of conducting a cyanation reaction to convert Ri from OH to CN, before or after the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II; preferably after the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II.

28. A process according to any one of claims 1 to 27, further comprising a step of conducting an amino protection reaction to convert F from hydrogen to Prot^NH, before or after the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II; preferably after the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II.

29. A process according to any one of claims 1 , 2, 4 and 7 to 26, wherein Ri in Formula I is OH and R2 in Formula I is hydrogen, and: further comprising a step of conducting a cyanation reaction to convert Ri from OH to CN immediately after the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II; and further comprising a step of conducting an amino protection reaction to convert R2 from hydrogen to Prot^NH immediately after the step of conducting the cyanation reaction to convert Ri from OH to CN.

30. A process according to any one of claims 1 , 3, 4 and 7 to 26, wherein Ri in Formula I is CN and R2 in Formula I is hydrogen, and: further comprising a step of conducting a cyanation reaction to convert Ri from OH to CN immediately before the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II; and further comprising a step of conducting an amino protection reaction to convert R2 from hydrogen to Prot^NH immediately after the step of oxidizing a reaction mixture comprising the compound of Formula I to give the compound of Formula II.

31 . A process according to any one of claims 27, 29 and 30, wherein the step of oxidizing the reaction mixture comprising the compound of Formula I to give the compound of Formula II, and the step of conducting the cyanation reaction to convert Ri from OH to CN, are conducted as a one-pot reaction.

32. A process according to claim 1 , wherein the ecteinascidin compound is selected from:

33. A compound according to Formula I: wherein Ri to R3 are as defined in any one of claims 1 to 7, with the proviso that when R2 is CONHPh then R3 is hydrogen.

34. The compound according to claim 33 wherein Prot^NH is selected from allylcarbamate (Alloc), 2,2,2- trichloroethylcarbamate (Troc), benzylcarbamate (Cbz), 9-fluorenylmethyl-carbamate (Fmoc), CSNHPh, and t-butylcarbamate (Boc), preferably t-butylcarbamate (Boc).

35. The compound according to claim 33 wherein R2 is H.

36. A compound according to claim 33 of formula:

HQ-1

37. A compound according to claim 33 of formula:

HQ-2

38. A compound according to claim 33 of formula:

39. A compound of formula: