JPS61171453A - Lower alkyl ester of racemic 2,2-disubstituted cis or trans-3-formylcyclopropane-1-carboxylic acid - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The subject of the invention is a compound of the general formula I in which R represents an alkyl group containing 1 to 6 carbon atoms and X contains 2 to 6 carbon atoms. or the two X groups together with the carbon atoms to which they are attached represent a cycloalkyl group containing from 3 to 7 carbon atoms] racemic 2.2-disubstituted ell or trans -5-
The cyclopancarboxylic acid ester of the formula (2) of the present invention is based on lower alkyl esters of formylcyclopropane-1-carboxylic acid.
Racemic 2. of the following general formula I (where X and R have the meanings given above)
2-disubstituted eel or trana-cyclopropane-1
, a lower alkyl half ester of a 3-dicarboxylic acid is reacted with a reducing agent selected from the group consisting of diporan and hydrogenated borohydride alkali, resulting in the following racemic 2,2-disubstituted all or tranll of general 2. -3
The lower alkyl ester of hydroxymethylcyclopropane-1-carboxylic acid is treated with the action of chromic acid in the presence of pyridine, the action of lead tetraacetate in the presence of pyridine, the action of manganese dioxide, chlorsuccinimide, then dimethyl It can be produced by a method characterized by carrying out the action of a reducing agent or reducing system selected from the following group: the action of a sulfide and the action of dimethyl sulfoxide after esterifying the alcohol functional group with a sulfonic acid.

This method is exemplified by Reaction Scheme I◇ In the general formula ■, R is methyl, ethyl, straight chain or branched chain propyl, straight chain or branched chain butyl, straight chain or branched chain pentyl, or a straight-chain or branched hexyl group, X in particular ethyl, straight-chain or branched puchyl, straight-chain or branched butyl, straight-chain or branched pentyl or straight-chain or branched hexyl or the two X groups together with the carbon atoms to which they are attached represent a cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl group.

The reduction of compound I to compound (I) with diborane is advantageously carried out in a solvent such as ethyl oxide.

This solvent is preferably tetrahydrofuran. This solvent may also be dimethyl sulfide.

Reduction with diborane is carried out with an excess of reagent.

Preferably 4 to 1 mole of monoester of diacid (■)
6 moles of diporane are used.

In order to carry out the reduction of compound (1) to compound (2), sodium borohydride or potassium borohydride is preferably used as the alkali borohydride.

The borohydride reduction is preferably carried out in a solvent consisting of an ether oxide, especially in tetrahydrofuran.

As the alkali borohydride, sodium borohydride is preferably used.

The reduction with a borohydride alkali is carried out in excess, preferably in an amount of about 2 mol per 1 mol of the acid ester (2).

An advantageous method of implementation consists in introducing a solution of the acid ester (1) into a solution of the borohydride alkali.

The oxidation of compound (1) to compound (2) with chromium in the presence of pyridine is preferably carried out in methylene chloride.

Oxidation by chromium in the presence of pyridine produces the compound ■
This is advantageously carried out using an excess of oxidizing agent corresponding to about 5 mol per mol of oxidizing agent.

The oxidation of alcohol ■ to aldehyde I by lead tetraacetate in the presence of pyridine is preferably carried out in the presence of excess pyridine. This can also be achieved by the action of chlorsuccinimide and then dimethyl sulfide.

Furthermore, the conversion of alcohol (■) into aldehyde (I) can be achieved by preparing a sulfone ester of alcohol (i), particularly p-)luenesulfonic acid ester, and then reacting dimethyl sulfoxide with this while heating in a basic medium. You can also do O me (1) 77 * f) asll= II K M
General formula of n b tL h e”11”°°1 structure l
Compounds of 11g1 and trans are both described in the literature ◇ The metal compound of the general formula l with the trans structure in which tra
Diester of ns-cyclopropane-1-carboxylic acid (
4) can be easily obtained by monosaponification.

Examples of these preparations include experiments in which X represents a methyl group or an ethyl group, or two substituents X together with their bonded carbon atoms represent a cyclohexyl group or a cyclopentyl group. It is shown in the section.

The trans-diester (4) itself is described in French Patent Application No. 76-59 filed on the same date by the applicant.
No. 552 [Name of the invention: 7-seki 2.2-di-substituted tra
Process for producing low melting alkyl ester of ns-cyclopropane-11s-dicarboxylic acid and novel ester of this acid]
By the method described in Fumar Meng.

It can be obtained by a one-step total synthesis by condensing an alkyl or alkyl maleate with the appropriate triphenylphosphonium I-μ generator.

A production example of diester (2) is shown in the experimental section.

Compounds of general formula l having an ets structure in which X is different from methyl are:
0 obtained by the series of reactions below, in this case ciB
-i1! Overrooting via (3) can be avoided.

It constitutes a purification process.

Examples of their preparation are given in the experimental section when X represents a methyl or ethyl group or when the two substituents X together with the carbon atoms to which they are attached represent a cyclopentyl or cyclohexyl group.

The importance of the above method of the present invention is that it
The fact is that aldehydes I having the ans structure can be produced in a limited number of steps and under conditions that are easy to industrialize. U-uh□9e□. 72° (many industrial uses to facilitate the acquisition of lopancarboxylic acids and subsequent conversion of these acids into insecticidal esters).

As mentioned above, starting compound ① is cis-based and tra-based
Both na systems can conveniently be obtained from the corresponding diesters (4) which themselves can be prepared in one step by total synthesis.

Furthermore, the method of the invention can be applied to ci of various different structures.
It appears to be an essential step that allows g- or trana-cyclopropanecarboxylic acid to be obtained by total synthesis.

The following reaction scheme (1) summarizes all the reactions that make it possible to obtain these cyclopropane carboxylic acids by total synthesis and shows the importance of the process of the invention in this series of reactions.

The compounds of general formula I described above, in which X is different from a methyl group, are new.

Among these compounds, the compounds of the general formula (1) mentioned above are particularly mentioned, and the compound name is as follows. Ethyl λ2-diethyl-3-formylcyclopropane-1-carboxylate, racemic tran8
-ethyl spiro(2,5]octane-2-formyl-1-carboxylate, racemic methyl cls-λ2-diethyl-3-formylcyclopropane-1-carboxylate, racemic cl!I-spiro[2,5]octane -Methyl-2-formyl-1-carboxylate.

The present invention also encompasses the intermediates whose names are as follows, particularly as new industrial compounds useful for carrying out the preparation of compounds of formula I.

racemic tran8-spiro(2,4)heptane-2-hydroxymethyl-1-methylcarboxylate, racemic tra
Ethyl n8-2.2-diethyl-3-hydroxy)f-cyclopropane-1-carboxylate, racemic tr&n8-
spiro(2,5:]]ethyl octane-2-hydroxymethyl 1-carboxylate, racemic cis-2,2-dimethyl-3-hydroxymethylcyclopropane-1-carboxylate, racemic cl!I-2,2 -diethyl-
Methyl 3-hydroxymethylcyclopropane-1-carboxylate, racemic trans-spiro(2,4)heptane-1,2-dicarboxylic acid monomethyl ester, racemic trans-spiro[2,5]]octane-1,2- monoethyl ester of carvone, monoethyl ester of racemic trana-2,2-diethylcyclopropane-1,s-dicarboxylic acid, racemic ail-2,2-diethylcyclopropane-1,3-
Monomethyl ester of dicarboxylic acid, monomethyl ester of racemic ciB-spiro[λ5]octane-1,2-dicarboxylic acid.

The following examples illustrate the invention without limiting it.

In these examples, the designation X+X=cyclopentyl or cyclohexyl means that X+X together with their attached carbon atoms represent a cyclopentyl or cyclohexyl group.

class alkyl ester (trans compound of general formula (■)) 4
10 moles of racemic 2.
A lower alkyl monoester of a 2-disubstituted trans-cyclopropane-1,5-dicarboxylic acid (compound of general formula (1)) is introduced and a solution of 4 x 10-'' moles of diborane in tetrahydrofuran, i.e. 4c!11s of 1N diborane is introduced. The solution was added dropwise under a nitrogen atmosphere, stirred, and concentrated under reduced pressure. To the residue was added 2 CC of water, extracted with ether, and the ether phase was washed with water and then chlorinated.) Washed with a saturated aqueous IJ solution and dehydrated. Concentrate and purify by chromatography on silica gel eluting with ether.

The experimental results obtained are summarized in the table below.

Trans compound (a) Racemic tran8-2,2-dimethyl-3-
Ethyl hydroxymethylcyclopropane-1-carboxylate (b) Racemic trans8-spiro[2,4]methylheptane-2-hydroxymethyl-1-carboxylate (e) Racemic trans-λ2-diethyl-3-hydroxymethylcyclopropane -1-Ethyl carboxylate (d) Racemic trall-spiro[2,5)octane-2-hydroxymethyl-1-carboxylic acid ethyl racemime 2-disubstituted tran8-cyclopropane-1
, 3-dicarboxylic acid (trana compound of general formula (1)) can be produced by the following method.

To 10-2 mol of racemic 2,2-disubstituted trans-cyclopropane-1,3-dicarboxylic acid diester [tran8 compound of 2A] was added 1.5 x 10-1 mol of potassium aqueous dispersion in 6 cyn" A solution formed in alcohol (an alcohol that esterifies the acid function of diester I) is added dropwise, the reaction mixture is refluxed for 3 hours, the alcohol is removed, 5 cm" of water is added, extracted with ether, The aqueous phase is sensitized to pH 1, the aqueous phase is extracted with ether, the ether phase is washed with water and then with saturated sodium chloride solution, dried, concentrated to dryness, enitel and petroleum ether (BP=35-75 °C] mixture (s
Purify by chromatography on silica gel using o:so) as eluent.

The experimental results obtained are summarized in the table below.

trans compound of formula (@) Monoethyl ethyl of racemic trans-2,2-dimethylcyclopropane-1,3-dicarboxylic acid (used to prepare compound 1) (f) Racemic trans-spiro [2, 4] Monomethyl ester of heptane-1,2-dicarboxylic acid (used to prepare compound S) ω racemic trans-spiro[z5]octane-1,
Monoethyl ester of 2-dicarboxylic acid (used to prepare compound d) (h) Racemic tram! Monoethyl ester of -2,2-diethylcyclopropane-1,S-dicarboxylic acid (used to prepare compound C). A solution of 1 mmol of racemic ciG-2,2-dimethylcyclopropane-t3-dicarboxylic anhydride dissolved in 2-dihydrofene was slowly added to the solution. Add, cool to 20℃, keep at this temperature for 1 hour or 1 hour, cool to 0℃, and add 10%
Slowly dissipate with an aqueous solution containing hydrochloric acid to pH 3-4, extract with ether, combine the ether fractions, dry and concentrate, add to the remainder until a permanent color of diazomethane is obtained, and remove the solvent by distillation under reduced pressure. Remove the residue and remove the residue by 95%
Purification by chromatography on silica gel using a mixture of 5% benzene and 5% ethyl acetate as eluent gives the racemic C111-2,2-dimethyl-3-hydroxymethyl-1-carboxylic methyl ester. Yield is 6
7.5゛-〇 NMR spectrum δ = 1.20- L 60 ppm (Mani Teplet 2H) δ-t 2 G ppm (Singlet 6H)
δ= & 60 ppm (Singlet 5H) δ=
S, 80- & 86 ppm (Doublet 2H)
1δ=A 52 ppm (I H, alcohol) Example 3: Racemic 2.2-disubstituted C11l -5-hydroxymethylcyclopropane-1-carboxylic acid methoxy
Introducing y mmol (i.e., (or dimethyl sulfide) solution was slowly added at 0°C, stirred at 25°C for 2 hours and 30 minutes, the carbon dioxide was removed by vacuum distillation, 1051" of water was added, extracted with ether, and the organic The phases are combined, washed with water, dried and concentrated by distillation, and the residue is purified on silica gel using ether as eluent.

The experimental results obtained are summarized in the table below.

- Racemic c1m -2,2-dimethyl-3-hydroxymethylcyclopropane-1-carvone methyl (n) Racemic ail-spiro(2,5)octane-
2-hydroxymethyl-1-carboxylic methyl (0)
Racemic cis-2,2-dimethyl-3-hydroxymethylcyclopropane-1-carboxylic acid methyl (same as compound m) 0) Racemic c18-2,2-diethyl-3-hydroxymethylcyclopropane-1-methyl carboxylate (q) racemic eis-spiro[2,5)octane-
2-Hydroxymethyl-1-carboxylic methyl (same as compound n) Monomethyl ester of racemic 2,2-disubstituted a1g-cyclopropane-1,3-dicarboxylic acid of formula ■ used at the start of the process of Example 3 can be manufactured by the following method.

Under a nitrogen atmosphere, X mmol (yf) of racemic λ2-disubstituted trans-cyclopropane-t3-dicarboxylic acid diester (trana compound of general formula A), 149 mol (4sF) of potassium hydroxide and tcs'' of methanol (or The mixture of ethanol] was refluxed for 2 hours, the alcohol was removed by distillation, the reaction mixture was extracted with water, extracted with ether, dispersed with hydrochloric acid, the acidic aqueous phase was extracted with ether, and the ethereal phase was extracted with hydrochloric acid. was washed with a saturated aqueous solution of sodium chloride.

Dehydrate and concentrate to dryness under reduced pressure. The experimental results obtained are as follows: 0(r) Racemic trans-2,2-dimethylcyclopropane-1,
3-dicarboxylic acid (fl) Racemic trans-2,2-diethylcyclopropane-1,3-dicarboxylic acid (1) Racemic trans-spiro(2,5)octane-1,2-dicarboxylic acid (u) Racemic tran8- Spiro(2,4)heptane-1,2-dicarboxylic acid Racemic 2,2-disubstituted t of formula A used at the start of Step A
The diester of rall-cyclopropane-1,3-dicarboxylic acid is disclosed in French Patent No. 76-59552 of the same date by the applicant [name of the invention Niracemi 2.2].
Process for the preparation of lower alkyl esters of -disubstituted trans-cyclopropane-1,3-dicarboxylic acids and novel esters of this acid]. The compound 2A used in the above table for the preparation of the trans compound of formula 1 found in the preparation of Example 1 can be prepared in the following manner.

Racemic trans-λ2-dimethylcyclopropane = 1
．． Ethyl 3-dicarboxylate (compound A, X=methyl, R
= Ethyl] Production of [157
6f of triphenylisopropylphosphotium bromide is introduced, then α090t of butyllithium (L7CH
Slowly add a solution prepared by dissolving L156F in pentane at 0°C, stir for 30 minutes at 0°C, then introduce a solution prepared by dissolving L156F 7-malate diethyl ester in scc dimethoxyethane, and heat to 0°C. Stir for 15 minutes and raise the temperature to 20℃.
and stir again until decolorization, i.e. about 2 hours, add water, stir, extract with ether, wash the ether extract with water and then with saturated aqueous sodium chloride solution, dry, concentrate and under reduced pressure. It was rectified into 1108t of racemic tr&n! Ethyl l-2,2-dimethylcyclopropane-1,3-dicarboxylate is obtained.

BP=82°C/α7■Hgo This chemical compound is called compound a.

To carry out this reaction, diethyl fumarate can be replaced with ethyl maleate to produce compound α in the same yield and with the same properties.
- Diethylcyclopropane 551 triphenyl-5-pentylphosphonium iodide is introduced into 1500 CC of dimethoxyethane under nitrogen, and then 55 CH of 2.1N butyllithium in pentane solution is slowly added at 0°C,
Stir at 25℃ for 30 minutes, cool to 0℃, t, 4.4f
7 malic acid dimethyl ester/I/ (or 144 t maleic acid dimethyl ester) was introduced very slowly,
(It takes about 5 hours for the reaction mixture to decolorize) Stir at 25°C, add water, extract with ether, wash the ether extract with saturated aqueous sodium chloride solution, dry, concentrate to dryness, and remove the residue under reduced pressure. Rectified to the bottom, 6t of racemic tra
Methyl ns-2,2-diethylcyclopropane-1,3-dicarboxylate is obtained. BP=65℃/[14mug
(, MP=25-30°C. Called compound β.

NMR spectrum (carbon tetrachloride) δ = 0.76-1.08 ppm () riplet,
6H) δ = 124-2.92 ppm (FF le?pret, 4H) δ = 2.08 ppm (singlet, 2H) δ = 565 ppm (singlet, 6H)
In a similar manner starting with ethyl 7malate and 3-pentyltriphenylphosphonium iodide, racemic tran!
Ethyl I-2,2-diethylcyclopropane-1゜3-dicarboxylate (compound A%X=ethyl, R=ethyl)
Obtain 013p==33~85℃/l 5-HP o
It is called compound β1.

1168Bf in 15CC of dimethoxyethane under nitrogen! 5) Lifenil 3. - Pentylphosphomoium was introduced, and a solution of IIL05t butyllithium dissolved in 17cc of pentane was slowly added at 0°C.
Stir for 50 minutes at 0°C, introduce a solution of somaric acid dimethyl ester (1128f) in 5CC of dimethoxyethane, stir for 15 minutes at 0°C, reduce the temperature to 2
Raised to 0° C., stirred until decolorized, i.e. about 2 hours, added water, stirred, worked up as above, chromatographed the residue on silica gel, and added a benzene mixture containing 3 parts of ethyl acetate. The racemic tran8-2.2-diethylcyclopropane of 111509 was eluted with
Methyl 1,3-dicarboxylate is obtained.

It is called compound β.

16 in 4500 CC of dimethoxyethane under nitrogen atmosphere.
02 triphenylcyclopentylphosphonium bromide was introduced, 160 CC of 2.1N butyllithium in pentane solution was added (simmered at 0 °C), stirred for 30 minutes at 25 °C, cooled to 0 °C, and 452 t of fumaric acid was added. Introduce the acid dimethyl ester slowly, stir at 25°C until the reaction mixture is decolored (requires about 5 hours), add water,
Extract with ether, process as described above, 1! L2F racemic trans-spiro(264)heptane-1,2
-Ethyl dicarboxylate is obtained. BP=89℃/lO
8 Kasumi HP0 Called compound r.

NMR spectrum (dimethyl sulfoxide) δ = 14
0-1.80 ppm (Multiplet, 8H) δ=
122 ppm (singlet, 2H) δ=564
ppm (singlet, 6°H) 1152 (F) Jl-ionized IJ phenylcyclohexylphosphonium was introduced into dimethoxyethane of 3200 (C) under a nitrogen atmosphere, and 1
Slowly introduce 12CC of 2.1N butyllithium in pentane solution at 0℃, stir for 3 minutes at 25℃,
Cool to 32.52°C, introduce 7-marinated dimethyl ester very slowly, stir at 25°C until the reaction mixture is decolorized (requires about 5 hours), add water and extract with ether. , the ethereal extract was washed with saturated aqueous sodium chloride solution, dried, concentrated, and the residue was rectified under reduced pressure to obtain the racemic tram!l-spiro (215
) Octane-1,2-dicarboxylic methyl is obtained. B.P.
=133-138°C/α5■Hf 0 Compound δ is called.

NMR spectrum (dimethyl sulfoxide) δ=t20
-1.80 ppm (multiplet, 10H) δ=2
．． 12ppm (singlet, 2H) δ=568pp
m (singlet, 6H) In a similar manner, starting with cyclohexyltriphenylphosphonium bromide and the 7-marginated methyl ester, racemic trans-spiro (2,
5) O//-1,2-dicarboxylic ethyl (compound A
, X+X=cyclohexyl, R=ethyl]. B.P.
=90-103°C/(LO8cIRHP.

It is called compound δ1.

5 with xf trans-diacid under vacuum in a sealed tube.
xt with acetic anhydride was heated at 220°C for 6 hours,
Cool, remove excess acetic anhydride and generated acetic acid, and
51" of water and 12" of activated carbon are added, heated at 120 DEG C. for 2 hours and 30 minutes, heated, and then the water is removed by vacuum distillation. The remaining solid is pure all-diacid.

The experimental results obtained are as follows.

City (ma) Racemic eill -2,2-dimethylcyclopropane-1,3-dicarboxylic acid (b) Racemic ei8-2,2-diethylcyclopropane-1,3-dicarboxylic acid (t) Racemic clS-spiro[: 2.5 ]] Octane-12-dicarboxylic acid) Racemic cis-spiro(L') heptane-1°2-dicarboxylic acid ) of acetyl chloride was heated to 40° C. for 2 hours, cooled, excess acetyl chloride and the resulting vinegar residue were removed by vacuum distillation, and the desired all
- Obtain the anhydride.

The experimental results obtained are as follows◇ (z) Racemic eia -2,2-dimethylcyclopropane-1,3-dicarboxylic anhydride (a1) Racemic cill -2,2-diethylcyclopropane-1 3-dicarboxylic anhydride (BL) racemic eis-spiro[2,5]octane-1
, 2-dicarboxylic anhydride (i.e., xt
), 5 drops of pyridine were added, stirred for 16 h at 20 °C, excess methanol was removed by distillation), and the residue was chromatographed on silica gel with ether as eluent. and purify it to the desired e
The monomethyl ester of the i8-diacid is obtained.

The experimental results obtained are as follows.

(C1] Racemic ell!l Monomethyl ester of -2,2-dimethylcyclopropane-1,3-dicarboxylic acid (dl) Racemic ci8-monomethyl ester of 2,2-diethylcyclopropane-1,3-dicarboxylic acid (e , ] ] ] ] Racemic cis-spiro 2ts ) Monomethyl ester of octane-1,2-dicarboxylic acid 4C
1.5 x 104 mol of Cr (h/pyridine complex) was introduced into H dichloroethane under a nitrogen atmosphere to form a suspension, and 1.
0-8 mol of 2,2-disubstituted trans obtained in Example 1
-Lower alkyl ester of 3-hydroxymethylcyclopropane-1-carboxylic acid <trans of general formula (■)
A solution prepared by dissolving Compound] in methylene chloride of ICH was added dropwise, stirred for 2 hours, ether was added, the resulting insoluble matter was separated, concentrated by vacuum distillation, and chromatographed on silica gel using ether as an eluent. and refine it.

The experimental results obtained are as follows.

Trans compound of general formula I (i) Racemic trans! -2,2-dimethyl-3
-Ethyl formylcyclopropane-1-carboxylate, obtained by starting from compound (a) of Example 1 (j) Racemic trans-spiro(2e')methyl heptane-2-formyl-1-carboxylate, Example 1 −(kJ racemic t
ethyl rans-2,2-diethyl-3-formylcyclopropane-1-carboxylate, obtained starting from compound (e) of Example 1, 1(1) racemic t
rans-spia [: 2,5]] octane-2-
Formyl-1-carboxylic ethyl powder was added to a solution of anhydrous chromium [/pyridine hydrochloride complex of
sf) of 2,2-disubstituted cis-3-hydroxymethylcyclopropane-1-carboxylic acid was slowly added, stirred at 20°C for 2 hours, filtered and concentrated, and the residue was Purify by chromatography on silica gel using ether as eluent.

The experimental results obtained are summarized in the table below.

(fl) Racemic eia -Methyl ester of 2,2-dimethyl-3-formylcyclopropane-1-carboxylic acid (g8) Racemic ei! I -2,,2-jechini-5-
Methyl ester of formylcyclopropane-1-carboxylic acid (hl) racemic eig-spiro(2,5)octane-2
-Formi A-1-Carboxylic acid methyl ester reaction formula

Claims (3)

[Claims] (1) The following general formula I ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (I) (Here, R represents an alkyl group containing 1 to 6 carbon atoms, and X represents an alkyl group containing 2 to 6 carbon atoms. or the two X groups together with the carbon atoms to which they are attached represent a cycloalkyl group containing from 3 to 7 carbon atoms) racemic 2,2 - Lower alkyl esters of disubstituted cis or trans-3-formylcyclopropane-1-carboxylic acids. (2) Claim 1 in which the compound name is as follows:
Compounds of general formula I as described in Section. Racemic trans-spiro[2,4]methyl heptane-2-formyl-1-carboxylate, Racemic trans-2,2-diethyl-3-formylcyclopropane-1-carboxylate, Racemic trans-spiro[2,5] ] Ethyl octane-2-formyl-4-carboxylate, racemic cis-2,2-diethyl-3-formylcyclopropane-4-methyl methyl carboxylate, racemic cis-spiro[2,5]octane-2-formyl-4 -Methyl carboxylate. (3) A new industrial compound whose compound name is as follows. Racemic trans-spiro[2,4]heptane-2-hydroxymethyl-4-carboxylic acid methyl, racemic tri
Ethyl ns-Z2-diethyl-3-hydroxymethylcyclopropane-1-carboxylate, racemic trans-spiro[2,5]octane-2-hydroxymethyl-1-
Ethyl carboxylate, racemic cis-2,2-dimethyl-
Methyl 5-hydroxymethylcyclopropane-1-carboxylate, racemic cis-2,2-diethyl-3-hydroxymethylcyclopropane-1-methyl carboxylate, racemic trans-spiro[2,4]heptane-1,2-
Monomethyl ester of dicarboxylic acid, racemic trans-spiro[2,5]octane-1,2
-monoethyl ester of dicarboxylic acid, racemic trans-2,2-diethylcyclopropane-
Monoethyl ester of 1,3-dicarboxylic acid, racemic c
Monomethyl ester of is-2,2-diethylcyclopropane-1,3-dicarboxylic acid, monomethyl ester of racemic cis-spiro[2,5]octane-1,2-dicarboxylic acid.