CA1274518A - 2-(substituted sulfamyl)-6-nitrobenzoic acids, useful as adjuncts to radiation therapy - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Derivatives of 2-(substituted sulfamyl)-6-nitrobenzoic acids are disclosed, wherein at least one of the sulfamyl substituents is selected from amino-(lower alkyl), (lower alkyl)-amino-(lower alkyl), or di(lower alkyl)-amino-(lower alkyl), hydrogen, lower alkyl, hydroxy-(lower alkyl), allyl, or when taken together with the nitrogen of the sulfamyl moiety, form a heterocyclic ring. These compounds have activity in increasing the sensitivity of hypoxic tumor cells to therapeutic radiation.
Also disclosed are methods of preparing such compounds ana pharmaceutical compositions including such compounds.

Description

127~51~

BACKGROUND OF THE INVENTION
This invention relates to derivatives of 2-(substituted sulfamyl)-6-nitrobenzoic acids, specifically esters, amides and N-substituted amides thereof used as sensitizers of hypoxic tumor cells to therapeutic radiation.
It also relates to the process of preparing such * ~
t , ., ' '' ' ' - ~ ' . .
:

',.' -" ' - ' ' " ' ' lX74518

2-chlorosulfonyl-6-nitro benzoate ester and aminating said 2-chlorosulfonyl benzoate ester to produce the corresponding 2-(substituted sulfamyl)-6-nitrobenzoic ester, and converting said ester to the substituted carbosamide.
At the present time, certain other unrelated compounds are in experimental clinical use as radia-tion sensitizers. However, these compounds -- for example, metronidazole and misonidazole -- suffer from the drawback that they also cause neurotoxicity which limits their usefulness. The compounds of the present invention are effective radiation sensi-tizers, and are believed to have a more favorable therapeutic ratio.
pETAI~ED DESCRIPTION OF THE INVENTION
The compositions of the present invention are nitrobenzenesulfonamide compounds of the formula ~2 /
2 ~ 1 I

wherein Rl is hydrosy, hydrosy-(lower alkosy), lower alkosy, alkosy-(lower alkoxy), allylosy, amino, monoalkylamino, dialkylamino, hydrosyalkyl-amino, di(hydrosyalkyl)-amino, or allylamino.

.' ~ , `.
- - .
' ~ ' -12745~8 -R2 and R3 are each separately hydrogen, lower alkyl from 1-4 carbon atoms, hydrosy~(lower alkyl), allyl, amino-(lower alkyl), ~lower alkyl)-amino-(lower alkyl), di(lower alkyl)-amino-(lower alkyl), (hydrosyalkyl)-amino-(loweralkyl), (hydroxyalkyl)-alkylamino-(loweralkyl) or di(hydroYyalkyl)-amino-(loweralkyl) or when taken together along with the nitrogen to which they are attached represent a heterocyclic ring æelected from morpholino, aziridinyl, azetidinyl, pyrrolidyl, piperidyl, or R4-substituted-3-o~opiperazin-l-yl (-N ~-R4) wherein R4 is hydrogen, lower alkyl of from 1-4 carbons, or hydrosyalkyl of from 2-4 carbons.
The 2-(substituted sulfamyl) derivatives of 6-nitrobenzoic acid, ester and amide compounds of the present invention are prepared in the following manner:
A substituted nitrobenzoate ester or nitro-benzamide having a 2-chlorosulfonyl substituent in an aprotic solvent such as tetrahydrofuran, diosane, dimethosyethane, or chloroform is treated with at least an equimolar amount of an amine of the formula ~
N-H II

wherein R2 and R3 are as aescribed hereinabove.

~74~ 8 4153P~1267A - 4 - 17223ICY

It is preferred to carry out the reaction in the presence of a base in sufficient amount to neutralize the hydrogen chloride formed in the course of the reaction. The base utilized may be a tertiary amine such as triethylamine or pyridine. On the other hand the same results may be produced by adding at least twice the molar amount of reactant amine theoretically required. In this event, the reactant amine is utilized both to form the sulfonamide and to neutralize the hydrogen chloride formed in the ~ amination reaction.
The temperature at which the reaction is carried out is not critical and may vary from 0-100C or at the reflus temperature of the solvent, if under 100C. The reaction temperature is preferably maintained at about 0-25C for a period of 1-24 hours. The amination reaction may be formulated as follows:

~ 1 R / ~ 1 NO2 ~ NO2 wherein Rl, R2 and R3 are as defined hereinabove.
The starting materials for the process are either known or are readily prepared from the known 2-amino-6-nitrobenzoic acid by a process of esterification followed by diazotization of the amino ~27~S18 group and treating the formed diazonium compound with S2 in the presence of CuC12 whereby the desired starting 2-chlorosulfonyl-6-nitrobenzoate ester is formed.
The ester derivatives of this invention may also be prepared by esterification of a carbosylic acid of formula I (Rl~OH). Established methods for the esterification of carbo~ylic scids containing basic groups may be used. These include reaction with diazoalkanes or with alcohols under strongly acidic conditions.
The benzamide derivatives of this invention may be prepared by reaction of a 2-monosubstituted sulfamyl-6-nitrobenzoate ester of formula III or a 2-substituted-4-nitro-2H-1,2-benzisothiazol-

3-one l,l-dioxide of formula IV with at least one equivalent of ammonia or a mono- or dialkyl-substituted amine of formula II.

~12NHR

III IV

In formulas III and IV, R2 is as ~escribed hereinabove and R5 is either lower alkyl or hydro~y-(lower alkyl). The reaction is carried out in a suitable solvent such as a lower aliphatic alcohol or a polar aprotic solvent such as ~Z7~518 dimethylformamide, dimethylsulfo~ide or others such aæ tetrahydrofuran, glyme, diglyme, chloro~orm or methylenechloride. The reaction temperature is not critical and may vary from 0-100C, preferably from S about 250-500C for a period of 1 to 10 days. When low boiling amines are used, the reaction may be run in a sealed vessel.
~ The compounds of this invention may also be - prepared by alkylation of an amine with an amide or ester of formula V wherein Rl and R2 are as defined hereinabove and R6 is an alkylating moiety ~uch as haloalkyl, alkylsulfonylo~yalkyl or aryl-sulfonylosyalkyl.
~2 ~f 2NR6 ~ ~

The reaction is carried out in a suitable aprotic solvent such as dimethylformamide, acetoni-tr~le or the like. The reaction temperature may varyfrom 50C to the boiling pcint of the solvent for a period of 1 to 10 days. When low boiling amines are uæed, the reaction may be run in a æealed ~essel.
It is preferred to carry out the reaction in the presence of a base in sufficient amount to neu~ralize the acid formed in the course of the reaction. The ., , . -, . . . .
:. . ' ` " ~, :, .' ' '' - ' . , 4153P~1267A - 7 - 17223ICY

base utilized may be a tertiary amine such as a trialkylamine or pyridine. Alternatively, at least twice the molar amount of reactant amine theoretic-ally required may be used. In this event, the reactant amine is utilized hoth to form the desired product and to neutralize the acid formed in the amination reaction.
The alkylating agents of formula V are readily prepared from the corresponding alcohols by established methods.
The method of treatment of human patients or domestic animals undergoing radiation treatment of malignant disease processes employs the compounds of the present invention in pharmaceutical compositions that are administered orally or intravenously. The dose employed depends on the radiation protocol for each individual patient. In protocols where the radiation dose is divided into a large number of fractions, the drug can be administered at intervals in the schedule and not necessarily with each radiation treatment. It should be noted that the compounds of the present invention are not intended for chronic administration. In general, the drug is administered from 10 minutes to 5 hours prior to the radiation treatment in a dosage amount of between 0.25 to about 4.0 grams per square meter of body surface.
- The aosage range given is the effective dosage range and the decision DS to the e~act dosage use~ must be made by the administering physician based on his judgement of the patient's general physical condition. In determining the dose for the , - . ~ .
, ~ .
- , , .
''. ' ' ' ' . ' ' ' ' ' - .
.

individual patient, the physician may begin with an initial dose of 0.25 g/square meter of body surface to determine how well the drug is tolerated and increase the dosage with each sùcceeding radiation treatment, observing the patient carefully for any drug side effect. The composition to be administered i8 an effective amount of the active compound and a pharmaceutical carrier for said active compound.
The dosage form for intravenous administra-tion is a sterile isotonic solution of the drug.Oral dosage forms such as tablets, capsules, or eli~irs may also be used.
Capsules or tablets containing 2S, 50, 100 or 500 mg of drug/capsule or tablets are satisfactory for use in the method of treatment of our invention.
The following esamples are intended to illustrate but do not limit the process of prepara-tion, product, compositions, or method of treatment aspects of the invention. Temperatures are in degrees Celsius unless otherwise indicated throughout the application.

E~amples Part A - Esampleæ of compounds in which at least one of R2 and R3 is a basic substituent.

~Ç~
- SteP A: Methyl 2-Amino-6-nitrobenzoate A mi~ture of 2-amino-6-nitrobenzoic acid (11.9 g, 65.3 mmol), methyl p-toluenesulfonate (15.1 g, 81.1 mmol) and triethylamine (6.60 g, 65.3 mmol) in DMF (170 ml) was stirred under N2 at 60 for 18 hours. After removing DMF at 60 and 0.2 mm ~12'7~5~13 i pressure, the residue was dissolved in ETOAc and washed with a saturated solution of NaHCO3 followed by a saturated aqueous solution of NaCl. The EtOAc extract was dried (Na2SO4), filtered and concentrated under reduced pressure. Flash chromatography over silica gel and elution with 50 toluene-50% CHC13 gave methyl 2-amino-6-nitro-benzoate (7.6 g, 59.4%), m.p. 105-107.

Ste~ B: ~ethyl 2-Chlorosulfonyl-6-nitroben~oate To a suspension of methyl 2-amino-6-nitro-benzoate (7.6 g, 38.7 mmol~ in glacial acetic acid (37 ml) and conc. HCl (67 ml), cooled to -5, was added slowly a solution of sodium nitrite (2.~6 g, gl,4 mmol) in H2O (11.2 ml). After addition was complete, the mi~ture was ~tirred at -5 to 0 for an additional 30 minutes. Dur~ing this time, a solution of CuC12.2H2O (2.45 9? in H2O (8.5 ml) was prepared and added to a cold solution of SO2 (25 g, 0.39 mol) in glacial acetic acid (50 ml). The diazonium salt solution was then added in portions to the cooled SO2-CuC12 mi~ture. After stirring in an ice bath for 3 hours, the reaction mi~ture was allowed to warm to 20-25 and was stirred at this temperature for 18 hours. The reaction mi~ture was then poured onto ice ~500 9), the precipitated tan solid removed by filtration and dried to give the sulfonyl chloride (9.1 g, 84.3%), m.p. 152-4.

lZ74S-lL8 Methyl 2-tN-(2-Dimethylaminoethyl)aminosulfonyl]-6-nitrobenzoate Hydrochloride and 2-tN-(2-Dimethylamino-~shyll~miDos~ulfonyl-L-6-nitrobenzoic acid A solution of methyl 2-chlorosulfonyl-6-nitrobenzoate (500 mg, 1.79 mmol) and 2-dimethylamino-ethylamine (316 mg, 3.58 mmol) in THF (35 ml) was stirred in an ice bath for 1 hour then at 20-25 for 18 hours. After removing THF under reduced pressure, the residue was partitioned between saturated - Na2CO3 solution and EtOAc. The organic extract was washed (saturated NaCl solution), dried (Na2SO4), filtered and concentrated under reduced pressure. Chromatography over silica gel (elution 15 with 5% MeOH-95% CHC13) gave an oil which when triturated with EtOAc afforded 2-lN-(2-dimethyl-aminoethyl)aminosulfonyl]-6-nitrobenzoic acid (90 mg, 16%), m.p. 193 decomposed with effervescence.
Treatment of the EtOAc soluble fraction with anhydrous EtOH-HCl and recrystallization from EtOH-EtOAc gave the HCl salt of the methylester (250 mg, 38%), m.p. 170-173.

~X~MPLE 3 N,N-Dimethyl-2-[N-(2-dimethylaminoethyl)aminosulfonyl]-6-nitrobenz~mlde Hydrochloride A solution of methyl 2-lN-(2-dimethylamino-ethyl)aminosulfonyll-6-nitrobenzoate (200 mg, 0.544 mmol~ and 0.5 ml of a 40% agueous dimethylamine solution in methanol (5 ml) was allowed to stand at 20-25 for 18 hours. After concentrating under reducea pressure, the residue was treated with ~7'~51~

anhydrous ethanolic hydrogen chloride and recrystallized from MeOH-EtOAc to give the HCl salt m.p. 166-69.

N,N-Dimethyl-2-tN-(2-dimethylaminoethyl)-N-(2-hydroxy-ethyl)aminosulfonyll-~-ni~obenzamide ~ydrochloride ~tep A: N,N-Dimethyl-2-[N-(2-dimethylaminoethyl)-N-(2-(2-tetrahydro-2H-pyranylo~y)ethyl)amino-~ul~onyll-6-nitrobe~ ide To a suspension of N,N-dimethyl-2-[N-(2-dimethylaminoethyl)aminosulfonyl]-6-nitrobenzamide hydrochloride ~347 mq, 0.91 mmol) in DMF (5 ml) under N2 was added 50% NaH ~87 mg, 1.82 mmol). After stirring at 20-25 for 15 minutes until all of the NaH had reacted, a solution of 2-(2-bromoethoxy)tetra-hydro-2H-pyran in DMF (2 ml) was added. The solution was stirred at 20-25 under N2 for 20 hours and then concentrated under reduced pressure to remove most of the DMF. The residue waæ partitioned between EtOAc and a saturated aqueous solution of NaCl. After drying (Na2SO4) the EtOAc estract, filtering and concentrating, the residue was chromatographed over silica gel. Elution with 7% ~eOH-93~ CHC13 qave 100 mg of product.

~tep B: N,N-Dimethyl-2-tN-(2-dimethylaminoethyl)-N-(2-hydro~yethyl)aminosulfonyl]-6-nitro-benzamide Hvdrochloride A solution of the tetrahydropyranyl ether (100 mg) in THF (10 ml), N2O (5 ml) and HOAc (20 ml) was stirred at 50 for 24 hours. After concen-trating under reduced pressure, the residue was partitioned between EtOAc and saturated NaHCO3 solution. The EtOAc e~tract was washed (saturated NaCl solution), dried (Na2SO4), filtered and concentrated. The crude product waæ purified by conversion to the HCl salt and recrystallized (MeOH-EtOAc-he~ane) to gi~e 32 mg of product, m.p.
162-64 dec.

E~mple s N,N-Dimethyl-2-{N-t~-(N-(2-hydro~yethyl)-N-methyl-amino)-ethyl]-N-methylaminosulfonyl}-6-nitrobenz-amide Hydroaen O~alate step A: N,N-Dimethyl-2-tN-(2-methylsulfonylo~yethyl)-N-methylam~nosulfonyll-~-ni~Q~nzamide A solution of N,N-dimethyl-2-[W-(2-hydro~y-ethyl)-N-methylaminosulfonyll-6-nitrobenzamide,prep~d as desc~d in E~ple 9 USP 4,647,588, (1.0 g, 3.0 mm~l~ and methanesulfonyl chloride (0.71 9, 6.2 mmol) in pyridine (10 ml) was stirred at 20-25~ for one day.
After concentrating under reduced pressure, the residue was partitioned between ethyl acetate and lN
~ aqueous HCl. The ethyl acetate e~tract was washed ; with water, dried and concentrated. Pure mesylate (1.0 9) was obtained by flash chromatography over silica gel and elution with a 1~ methanol-99%
chloroform ~olvent mirture.

;~
, ' ,, ~311~d . ~ , .

.
: - . . .
, .

lZ74518 ~tep B: N,N-Dimethyl-2-{N-[2-(N-r2-hydrosyethyl)-N-methylamino)e~hyl]-N-methylaminosulfonyl}-6-nitrobenzamide Hydro~en O~alate A solution of N,N-dimethyl-2-tN-(2-methyl-sulfonylosyethyl)-N-methylaminosulfonyl]-6-nitrobenz-amide (0.50 g, 1.2 mmol) and 2-(methylamino)ethanol (0.22 g, 2.9 mmol) in acetonitrile (20 ml) was stirred at reflus for 20 hours. After concentrating under reduced pressure, the residue was parti~ioned between ethyl acetate and water. The ethyl acetate layer was dried (Na2SO4), filtered and concentrated. Flash chromatography of the residue over silica gel and elution with 5% methanol-95% chloroform gave 400 mg of pure product as an oil. The hydrogen osalate salt, mp 159.0-162.0, was prepared for analysis.

N,N-Dimethyl-2-1N-(2-piperidinoethyl)-N-methylamino-,sul~onyll-6-ni~Q]2~nZamide Hydrochloride A solution of N,N-dimethyl-2-1N-(2-methyl-sulfonylosyethyl-N-methylaminosulfonyl]-6-nitrobenz-amide (0.41 g, 1.0 mmol) and piperidine (0.17 g, 2 mmol) in acetonitrile (20 ml) is stirred at reflus for 20 hours. The product is isolated following the procedure of Esample 5, Step B and converted to the hydrochloriae salt with anhydrous ethanolic hydrogen chloride.

. . ' :

lZ74518 ~ amples Part ~ - E~amples in which each of R2 and R3 is a non-basic substituent.

Methyl 2-tN-(2-Hydrosyethyl)-N-methylaminosulfonyl]-6-ni~robenzoate N-Methylethanolamine ~2.96 9, 39.4 mmol) was added to a golution of methyl 2-chlorosulfonyl-6-nitrobenzoate (5.5 g, 19.7 mmol, prepared according to Esample 1 of Part A, ~UPra) in THF (150 ml) and the misture ~tirred at 20-25 for 18 hours. After removing THF under reduced pressure, the residue was partitioned between EtOAc and H2O. The organic estract was washed with saturated NaCl solution and dried (Na2SO4). Flash chromatography of the residue over ~ilica gel and elution with 1% MeOH-99 CHC13 afforded pure sulfonamide. Recrystallization from EtOAc-hesane gave analytically pure product ~5.2 9, 82.9~), m.p. 98-101-.
;

Methyl 2-[N,N-Di~2-hydro~yethyl)aminosulfonyl]-6-~Q~enzoate _ _ A 601ution of di~2-hydrosyethyl)amine ~0.76 g, 7.2 mmol) in THF ~10 ml) was added to a solu~ion of methyl 2-chlorosulfonyl-6-nitrobenzoate ~1.0 9, -~ 3.6 mmol) in THF ~10 ml) and the misture stirred at 20-25~ for 18 hours. After removing THF under ~ 30 reduced pressure, the crude product was estracted - ~ into EtOAc which was then washed ~H2O), dried (Na28O4), filtered and concentrated under reduced pressure. Fla~h chromatography of the residue over .

, ~, - - , . . .

-. . .

: . , .

~2~7~5~8 4153P~1267A - 15 - 17223ICY

silica gel and elution with 5% MeOH-95% CHC13 gave pure sulfonamide. Analytically pure material (0.56 g, 44.8%), m.p. 92-3, was obtained upon recrystal-lization from EtOAc-he~ane.

EXA~SPLE 3 Methyl 6-Nitro-2-t3-o ~-1-pip,e~ ~inylsulfonyl¦benzoate Piperazin-2-one ~0.36 g, 3.6 mmol) was added to a mixture of methyl 2-chlorosulfonyl-6-nitro-benzoate (1.0 g, 3.6 mmol) and triethylamine (0.37 g, 3.6 mmol) in CHC13 (120 ml) and the resulting solution stirred at 20-25 for 18 hours. Removal of CHC13 under reduced pressure and flash chromato-graphy of the residue over silica gel (elution with 5% MeOH-95% CHC13) afforded pure sulfonamide ~1.2 g, 96.8%). Recrystallization from MeOH-H2O gave an analytical sample, m.p. 189-91.

EXAMPL~ 4 Met~yl 2-rN-Morpholinosul~Qnyll-6-nitrobenzoate A solution of morpholine (1.25 g, 14.3 mmol) in THF (20 ml) was added over 30 minutes to a stirred, cooled solution of methyl 2-chlorosulfonyl-6-nitrobenzoate (2.0 g, 7.15 mmol) in THF (20 ml).
After stirring at 20-25 for 18 hours, THF was removed under reduced pressure. The residue was partitioned between EtOAc and saturated NaCl-H2O
and the EtOAc e~tract was washed with H2O, dried (Na28O4), filtered and concentrated. Recrystal-lization from MeOH-EtOH gave pure sulfonamide (1.7 g, 72%), m.p. 145-8.

-,~ " ' ' ` ' ", ' ' -.
-~ ' , ' . .
' ' ~ - -~274518 E~CAMPLE 5 Methyl 2-[N-(2-Hydro~yethyl)aminosulfonyl]-6-nitrobenzoate A solution of methyl 2-chlorosulfonyl-6-nitrobenzoate (0.50 g, 1.79 mmol) and ethanolamine (0.33 g, 5.4 mmol) in THF (20 ml) was stirred at 20-25 for 18 hours and then concentrated under reduced pressure. Product was estractea into EtOAc which was then washed (H20), dried (Na2S04), filtered and concentrated under reduced pressure.
- The residue was recrystallized from EtOAc-hesane to give pure sulfonamide (0.28 g, 51.4%), m.p. 110-12.

N-(2-~ydrosyethyl)-2-lN-(2-hydrosyethyl)aminosulfonyl]-6-nitrobenzamide Step A: 2-(2-Hydrosyethyl)-4-nitro-2H-1,2-benziso-thiazol-3-one l.l-diosi~e ~o approsimately 2 ml of ethylene oside cooled in an ice bath was added a suspension of

4-nitro-2H-1,2-benzisothiazol-3-one l,l-dioside (2.0 g, 8.76 mmol) in H20 (140 ml). After stirring in the ice bath for 1 hour, the misture was allowed to stir at 20-25 for 18 hours. Water was removed under reduced pressure and the residue flash chromatographed over silica gel. Elution with 2~ isopropanol -98%
CH2C12 gave product which was recrystallized from EtOAc-hesane to qive the 2-hydrosyethyl derivative ~0.39 g, 16%), m.p. 140-1.
Step B: N-(2-Hydrosyethyl)-2-tN-(2-hydrosyethyl)amino-sulfonyll-6-nitrobenzamide A 801ution of 2-(2-hydrosyethyl)-4-nitro-2H-1,2-benzisothiazol-3-one l,l-dioside (100 mg, 0.37 . ~'' ' ~

. - .

:. - . .
-'; ': ' ' ' ~. ~ , .
. . ' . - - .

1274S~8 mmol) and ethanolamine (24 mg, 0.39 mmol) in THF (5 ml) was allowed to stand at 20-25 for 3 days. After removal of THF under reduced pressure, the residue was recrystallized from MeOH-EtO~c-he~ane to give 112 mg (91%) of product, m.p. 176.5-177.5.

~X~MP~E 7 Allyl ~=rN-Morpholinosulfo~y~l-6-nitrobenzoate ~teD A: Allyl 2-Amino-6-nitFo~nzoate A misture of 2-amino-6-nitrobenzoic acid (2.0 g, 11 mmol), allyl chloride ~1.05 g, 13.7 mmol) and triethylamine ~1.11 9, 11 mmol) in DMF ~50 ml) was stirred at 60 for 18 hours. After concentrating under reduced pressure, the residue was e~tracted with EtOAc which was then washed with saturated NaHCO3 solution and saturated NaCl solution, dried ~Na2SO4) and filtered. EtOAc was removed under reduced pressure and the residue chromatographed over silica gel. Elution with 50~ he~ane-50~ CHC13 gave the allyl ester ~1.1 g, 45%). An analytical sample, m.p. 54-5, was obtained upon recrystallization from toluene-hesane.
,, ~tep B: Allyl 2-Chlorosulfonyl-6-nitrobenzoate To a suspension of allyl 2-amino-6-nitro-benzoate (3.3 g, 14.9 mmol) in glacial acetic acid ~80 ml) and conc. HCl (26 ml) cooled to -5 was added slowly a solution of sodium nitrite (1.10 g, 15.9 mmol) in H2O (6 ml). After aadition was complete, the mi~ture was stirred at -5 to 0 for an additional 30 minutes. This diazonium salt solution was then added in portions to a cold solution of S2 (10 g, 0.156 mol) and CuC12-2H2O (1.19 g) - ' : - -.

, 1274S~8 in acetic acid (20 ml) and H2O (4 ml). After stirring in an ice ~ath for 3 hours, the reaction misture was allowed to warm to 20-25 and then poured on to ice (500 g). The solid sulfonyl chloride was filtered off and dried to give 3.5 9 (77.4~) of product, m.p. 68-70. An analytical sample, m.p.
70-72, was obtained upon recrystallization from - n-butyl chloride-hesane.

Ste~ C: Allyl 2-~N-Morpholinosulfonyl]-6-nitrobenzoate A ~olution of morpholine (1.63 g, 18.7 mmol) in THF (30 ml) was added over 25 minutes to a stirred and cooled solution of allyl 2-chlorosulfonyl-6-nitrobenzoate (2.85 g, 9.3 mmol) in THF (80 ml).
After stirring at 20-25 for 18 hours, THF was removed under reduced pressure and the residue partitioned between EtOAc and saturated NaCl solution. The EtOAc estract was dried (Na2SO4), filtered and concentrated to give a quantitative yield of the sulfonamide, m.p. 145-7. An analytical sample, m.p. 150-2 was obtained upon recrystalliza-tion from MeOH.

EXAMP~E 8 N,N-Dimethyl-2-tN-(2-hydrosyethyl)aminosulfonyl]-6-nitrobenzamide A solution of methyl 2-tN-(2-hydrosyethyl)-aminosulfonyl]-6-nitrobenzoate (4.58 g, 15.1 mmol) in absolute MeoH (50 ml) was added to a solution of dimethylamine (6.8 g, 0.15 mol) and potassium tert-buto~ide (0.68 ml of a 0.262 M solution in tert-butanol) in absolute MeOH (100 ml). After stirring -:
' . .
- ' 1274S~8 at 20-25 for 4 days, ~olvents were removed under reduced pressure. The residue was dissolved in EtOAc and washed with 0.5N HCl followed by a saturated aqueous NaCl solution. The EtOAc e~tract was dried (Na2S04), filtered and concentrated to give 4.2 g (88~) of product.

~XA~PLE 9 N,N-Dimethyl-2-tN-(2-hydrosyethyl)-N-methylamino-~ulfonyll-6-nitrobenzamide A solution of N,N-Dimethyl-2-~N-(2-hydro~y-ethyl)aminosulfonyll-6-nitrobenzamide (3.97 9, 12.5 mmol) in dry DMF (40 ml) was Ddded slowly to a stirred ~u~pension of 50~ NaH (0.60 g, 12.5 mmol) in 15 dry DMF ~10 ml) under N2 at 20-25. After formation of the ~odium salt was complete, a solution of methyl p-toluenesulfonate (2.40 g, 12.9 mmol) in DMF (4 ml) was added and the reaction mi~ture stirred at 20-25- for 20 hours and then at 60 for 23 hours.
The orange solution was mised with EtOAc (400 ml) and the white solid which formed was filtered off. This :. .
precipitate was washed with EtOAc (100 ml). The ; combined EtOAc solutions were washed with a saturated aqueous NsCl ~oIution, dried (Na2804), filtered and concentrated under reduced pressure. Pure product, mp 107-08-, 2.5 g (60~) was obtaineq by flash chromatography over ~ilica gel and elution with 65~ n-butylchloride-35~ acetonitrile solvent ;mi~ture.
, ~
~ 30 -~

., -~.

, , ~2~45~8 ~amEle 10 Methyl 2-tN-(3-Hydro~ypropyl)aminosulfonyl~-6-nitrobenzoat~ _ A solution of methyl 2-chlorosulfonyl-6-nitrobenzoate (2.80g, 10 mmol) in 100 ml of THF was cooled to ice temperature and stirred in an ice-bath while a solution of 3-amino-1-propanol (99%) tl~67g~
22 mmol) was added dropwise over a period of 4S
minutes. Stirring in the ice-bath was continued for 30 minutes. The reaction mi~ture then was acidified by addition of 3.0 ml of 1.2N HCl. The THF was evaporated under reduced pressure and the residue taken up in 100 ml of ethyl acetate. After estracting this solution with 4 s 20 ml of saturated NaCl solution, the ethyl acetate was evaporated and the residue recrystallized from a misture of ethyl acetate and hesane to give 2.709 ~84.9%) of light yellow crystalline product, m.p., 87-88.5.

E~ample 11 Methyl 2-tN-(2-Hydrosy-l-propyl)aminosulfonyl~-6-ni~robenzoate A solution of methyl 2-chlorosulfonyl-6-- nitrobenzoate ~2.80g, 10 mmol) in 100 ml of THF was cooled in an ice-bath and stirrea while a solution of l-amino-2-propanol (1.659, 22 mmol) in 10 ml of T~F
was added dropwise over a period of 50 minutes.
After stirring an additional 30 minutes in t~.e ice-bath, the reaction misture was acidified by the addition of 3 ml of 1.2N HCl. The THF was evaporated under reduced pressure and the resiaue taken up in 100 ml of ethyl acetate. After estracting with 4 s 20 ml of saturated NaCl solution, the ethyl acetate .
.
.

.,, -., solution was dried over Na2SO4 and the solvent evaporated. The residue was crystallized from a misture of ethyl acetate and he~ane to give 2.02g (63.5%) of yellow crystalline product, m.p., 93.5-95O.
Esamp le 12 N,N-Dimethyl-2-tN-(3-hydro~ypropyl)aminosulfonyl]-6-nitrobenzamide Methyl 2-tN-(3-hydrosypropyl)amino sulfonyl]-6-nitrobenzoate (2.00g, 6.28 mmol) was dissolved in 60 ml. of methanol. Sodium methoside (1.0 ml of a O.lM solution in methanol) was added and the solution cooled in an ice-bath and stirred while a rapid stream of dimethylamine was passed into the vortex for 15 minutes. After stirring for 16-1/2 hours, during which time the temperature rose to 25, the methanol and e~cess dimethylamine were evaporated under reduced pressure. Flash chromatography of the residue on E. Merc~ silica gel 60 (230-400 mesh) developed with n-butyl chloride:acetonitrile in the ratio of 65:35 gave light yellow crystalline product, isolated in two fractions, each melting at 85-87.
The second fraction contained a small amount of a second component, visible on TLC. Recrystallization of each fraction from a misture of ethyl acetate and hesane gave 0.48g of product, m.p., 86-87.5 and 0.43g of product, m.p., 85.5-87. Each product was analytically pure.

Example 13 N,N-Dimethyl-2-tN-(2-hydrosy-1-propyl)aminosulfonyl]-6-nitrobenzamide Methyl 2-tN-(2-hydrosy-1-propyl)amino-sulfonyl]-6-nitrobenzoate (2.009, 628 mmol) was ~Z74518 dissolved in 60 ml of methanol. Sodium metho~ide (1.0 ml of a O.lM ~olution in methanol) was added and the solution cooled and stirred in an ice-bath while a rapid stream of dimethylamine was passed into the vorte~ for 15 minutes. Stirring in the ice-bath then was continued for 1 hour, when the flash was removed from the bath and the reaction mi~ture allowed to stand at room temperature overnight. The methanol and esce~s dimethylamine then were evaporated under reduced pressure and the residue shaken with ethyl acetate, 80 ml; 0.2N HCl, 10 ml; and saturat~d NaCl, 10 ml. The ethyl acetate layer was separated, e~tracted with 3 ~ 15 ml of saturated NaCl and evaporated to give a clear yellow oil. After drying 23 hours in vacuo, this product weighed 2.03 9.
Crystallization had started after 3 days.
Recrystallization from a misture of ethyl acetate and hesane gave 1.33g (63.9~) of product, m.p., 95.5-97.

E~ample 14 N,N-Dimethyl-2-[N-(3-hydro~ypropyl)-N-methylamino-sulfonyll-6-nitro~enzamide N,N-Dimethyl-2-lN-(3-hydro~ypropyl)amino-sulfonyl]-6-nitrobenzamide (1.37g, 4.13 mmol) in 12 ; 25 ml of DMF, was added dropwise to a suspension of 198 mg (4.13 mmol) of 50% NaH in 3 ml of DMF in an atmosphere of N2. When evolution of hydrogen was complete, a solution of methyl p-toluene sulfonate (0.794g, 4.14 mmol) in DMF, 2 ml, was added. The clear deep yellow solution was stirred at 25 for 17 hours, then at 60 for 23 hours. The solution then ~ was mised with 175 ml of ethyl acetate and the; precipitate that separated collected on a filter and ~ .;, . . ~ .
.
.
. ., . -,,- , . -.. . . .

: - . -, .

lZ74518 washed with 50 ml of ethyl acetate. The combined filtrate and washinqs were estracted with 6 ~ 25 ml of saturated NaCl solution and the ethyl acetate evaporated to give 1.66 9 of a clear yellow oil.
Flash chromatography over E. Merck silica gel 60 (230-400 mesh) gave 0.49g of a clear light yellow oil. ~his material was dissolved in 50 ml of CHC13, the solution estracted with 4 s 5 ml of lN
NaOH, then with 3 ~ 5 ml of saturated NaCl and dried over MgSO4. After evaporation of the CHC13, the residue was dissolved in ethyl acetate and the solution filtered to remove a trace of MgSO4.
Evaporation of the solvent gave 0.44g of light yellow crystalline product, m.p., 91.5-92.5.
ADDITIONAL EXAM~I~S
Part C

~_yl 2-chlorosulfonyl-6-nitrobenzoate SteP-A: Ethyl 2-Amino-6-nitrobenzoate A solution of 2-amino-6-nitrobenzoic acid (29.2 g, 0.16 mol), diethylsulfate (24.7 g, 0.160 mol) and triethylamine (16.2 g, 0.160 mol) in N-dimethylformamide (2SC ml) was stirred at 20-25 for 20 hours. After removing DMF at 60 and 0.2 mm pressure, the residue was flash chromotographed over silica gel and the ethyl ester (10.8 g) eluted first with toluene then with 50% toluene -S0% chloroform.
~tep B: ~L~ g~ -6-nit~Qb~n3Qate To a suspension of ethyl 2-amino-6-nitro-benzoate (10.8 g, Sl.2 mmol) in qlacial acetic acid ' '' , ' . ': ' ' ' ' . ' `
, ~ - : . .
., ' ~' - -.

12~4518 4153P/1267A ~ 24 - 17223ICY

(55 mL) and concentrated HCl (95 mL), cooled to -5, was added slowly a ~olution of sodium nitrite (3.79 9, 54.9 mmol) in H20 (15 mL). After addition was complete, the misture was stirred at -5 to 0 for an additional 30 minutes. During this time, a solution of CuC12-2H2O (4.10 9) in H2O (10 mL) was prepared and added to a cold solution of SO2 (32 g) - in glacial acetic acid (100 mL). The diazonium salt solution was added in portions to the cooled SO2-CuC12 mi~ture. After stirring in an ice bath for 3 hours, the reaction mi~ture was allowed to warm to 20-25D and then poured onto ice (800 g). The precipitated ~olid was removed by filtration and dried to give 10.62 g (70.7%) of the sulfonyl chloride, m.p. 102-105. An analytical sample, m.p.
107-08, was obtained upon recrystallization from EtOAc-he~ane. Anal Calc'd for CgH8ClNO6S C, 36.81; H, 2.75; N, 4.77.
Found: C, 36.84; H, 2.80; N, 4.77.
Ethyl 2-[N-(2-Dimethylaminoethyl)aminosulfonyl]-6-nitrobenzoate hydrochloride ELQm: Ethyl 2-chlorosulfonyl-6-nitrobenzoate A ~olution of N,N-dimethylethylenediamine ~1.5 g, 17 mmol) and N,N-diisopropylethylamine (2.2 g, 17 mmol) in tetrahydrofuran (25 mL) was added over 15 minutes to a stirred solution of ethyl 2-chloro-sulfonyl-6-nitrobenzoate (5.0 9, 17 mmol) in tetrahydrofuran (100 mL) cooled with an ice bath.
After addition was complete, the reaction misture was stirred at ice bath temperature for 1 hour, then at 20-25 for 20 hours. Tetrahydrofuran was removed under reduced pressure and the residue partitioned 12745~8 between ethyl acetate and water. The organic e~tract was dried ~Na2S04), filtered and concentrated under reduced pressure. The residue was treated with ethanolic-anhydrous hydrogen chloride and the hydrochloride salt recrystallized from methanol-ethylacetate-hesane to give 4.28 g (65.9%3 of product, m.p. 165-166 dec. Anal. Calc'd for C13HlgN306S-HCl: C, 40.89; H, 5.28; N, 11.00.
Found: C, 41.24; H, 5.52; N, 11.10.
ELQm: Methyl 2-tN-~2-Dimethylaminoethyl)amin ~ulf~nyll-6-nitrobenzoate Hydrochloride A solution of the methyl ester hydrochloride (367 mg, 1 mmol) in absolute ethanol (20 mL) containing sodium ethoside (1.26 mmol) was stirred at reflus for 15 hours under N2. After adding glacial acetic acid (0.1 mL) and concentrating under reduced pressure, the residue was partitioned between ethyl acetate and a saturated aqueous solution of sodium chloride. The ethyl acetate estract was washed with more agueous sodium chloride, dried (Na2S04), filtered and concentrated. The residue was converted to the hydrochloride ~alt with ethanolic-anhydrous hydrogen chloride and recrystallizea from 25 ethanol-ethyl acetate-hesane to give 110 mg (28.9%) of product. m.p. 163-4-. anal Calc'd for C13HIgN306S-HCl: C, 40.89; H, 5.28; N, 11.00;
Found: C, 41.21; H, 5.47; N, 11.14.

Methyl 2-tN-(2-Dimethylaminoethyl)-N-(2-hydrosyethyl)-- aminosulfonyll-6-nitrobenzoate HYdrochloride A solution of N-(2-dimethylaminoethyl)-ethanolamine (0.95 g, 7.15 mmol) in tetrahydrofuran ;~ .

. .

- . .

~:. ' . . ' -' ." ' ' '~ " ' - ` ' ' ' ' .
. ~' ~ . . ,- ~ . -t20 mL) was added over 10 minutes to a stirred solution of methyl 2-chlorosulfonyl-6-nitrobenzoate (1.0 g, 3.S8 mmol) in tetrahydrofuran (30 mL) cooled with an ice bath. After addition was complete, the S reaction misture was stirred at 20-25~ for 5 hours.
Tetrahydrofuran was removed under reduced pressure and the residue partitioned between ethyl acetate and water. The organic extract was dried (Na2SO4), filtered and concentrated under reduced pressure. The concentrate was flash chromatographed over silica gel and product eluted with 5% methanol - 95~ chloroform.
The hydrochloride æalt, m.p. 152.5-4.5 dec, 0.63 g, (42.9%), was obtained upon treatment of the purified base with ethanolic anhydrous hydrogen chloride and recrystallization from methanol-ethyl acetate~ Anal Calc'd for C14H21N3O7S: C, 40.82; H, 5.39; N, 10.20 Found: C, 41.00; H, 5.43; N, 10.34.

Ex~pLE 3 Isopropyl 2-~N-(2-Dimethylaminoethyl)aminosulfonyl]-6-~itrokenzoate HYdrochlori~e A solution of methyl 2-[N-(2-dimethylamino-ethyl)aminosulfonyl]-6-nitrobenzoate hydrochloride (12.0 g, 32.6 mmol) in dry isopropanol (500 mL) containing sodium isoproposide (39 mmol) was stirred at reflus under N2 for 18 hours. After adding glacial acetic acid (1 mL) and concentrating under reduced pressure, the residue was partitioned between ethyl acetate and water. The ethyl acetate estract was washed with a saturated agueous solution of sodium chloride, dried (Na2SO4), filtered and concentrated. The residue was converted to the hydrochloride salt with ethanolic anhydrous hydrogen ~Z ~S~8 chloride and recrystallized from methanol - ethyl acetate to give 4.0 9 (31%) of product, m.p.
187.0-190.0 dec. Anal ~alc~d for C14H21N3O6S-HCl~ C, 42.47; H, 5.60; N, 10.61 Found: C, 42.21; H, 5.95; N, 10.44.

Methyl 2-tN-(2-Piperidinoethyl)aminosulfonyl]-6-nitro-benz,,,,o~te Hydrochloride A solution of 1-(2-aminoethyl)piperidine (0.23 g, 1.79 mmol) and N,N-diisopropylethylamine (0.23 g, 1.79 mmol) in tetrahydrofuran (5 ml) is added over 15 minut,es to a stirred solution of methyl 2-chlorosulfonyl-6-nitrobenzoate (0.50 g, 1.79 m~ol) in tetrahydrofuran (25 ml) cooled with an ice bath.
The product is isolated following the procedure of Example 1 and converted to the hydrochloride salt with anhydrous ethanolic hydrogen chloride.

The foregoing specification and e~amples describe the invention to the e~tent necessary to illuætrate the principles and practice of the present invention. It will be understood that the scope of the present invention encompasses any modifications, deletions and variations as come within the present invention. The following claims also illustrate the nature of the invention.

Claims (10)

WHAT IS CLAIMED IS

1. A 2-(substituted aminosulfonyl)-6-nitro-benzoic acid, ester or amide of the formula wherein R1 is OH, alkoxy, hydroxyalkoxy, allyloxy, amino, monoalkylamino, dialkylamino, hydrosyalkylamino, di(hydroxyalkyl)amino or allylamino;
R2 and R3 are each separately hydrogen, alkyl, hydrosyalkyl, allyl, aminoalkyl, monoalkyl-aminoalkyl, dialkylaminoalkyl, (hydroxy-alkyl)amino-(loweralkyl), (hydroxyalkyl)-alkylamino-(loweralkyl) or di(hydrosyalkyl)-amino-(loweralkyl) or when taken together with the nitrogen to which they are attached comprise a heterocyclic ring radical selected from morpholino, aziridinyl, azetidinyl, pyrrolidyl, piperidyl, or R4-substituted-3-oxo-piperazino-1-yl wherein R4 is hydrogen, alkyl or hydroxy alkyl,

2. A 2-(substituted aminosulfonyl)-6-nitro-benzoic acid, ester or amide of the formula wherein R1 is OH, alkoxy, hydroxyalkoxy, allyloxy, amino, monoalkylamino, dialkylamino, hydroryalkylamino, di(hydrosyalkyl)amino or allylamino;
R2 and R3 are each separately hydrogen, alkyl, hydroxyalkyl, allyl, aminoalkyl, monoalkyl-aminoalkyl, dialkylaminoalkyl, (hydroxy-alkyl)amino-(loweralkyl), (hydroxyalkyl)-alkylamino-loweralkyl) or di(hydroxyalkyl)-amino-(loweralkyl) provided that at least one of R2 and R3 contain a basic substituent selected from amino-(lower-alkyl), (loweralkyl)-amino-(loweralkyl), di-(loweralkyl)-amino-(loweralkyl), (hydroxyalkyl)-amino-(loweralkyl), (hydroxyalkyl)-alkylamino-(loweralkyl) or di(hydroxyalkyl)-amino-(loweralkyl).

3. A pharmaceutical composition for enhancing the therapeutic effect of radiation which consists of an effective amount of a compound defined in Claim 1 and a non-toxic pharmaceutically accepta-ble carrier.

4. The compound of Claim 2 which is selected from methyl 2-[N-(2-dimethylaminoethyl)amino-sulfonyl]-6-nitrobenzoate hydrochloride; N,N-dimethyl-2-[N-(2-dimethylaminoethyl)aminosulfonyl]-6-nitrobenz-amide; 2-[N-(2-dimethylaminoethyl)aminosulfonyl]-6-nitrobenzoic acid; N,N-dimethyl-2-[N-(2-dimethylamino-methyl)-N-(2-hydroxyethyl)aminosulfonyl] 6-nitrobenz-amide; and N,N-dimethyl-2- N-[2-(N-(2-hydroxyethyl)-N-methylamino)ethyl]-N-methylaminosulfonyl-6-nitrobenz-amide.

5. A substituted aminosulfonyl-6-nitro-benzoic, ester or amide of the formula wherein R1 is alkoxy, hydroxyalkosy, allyloxy, amino monoalkylamino, dialkylamino, hydroxyalkylamino, di(hydroxyalkyl)amino or allylamino;
R2 ana R3 are each separately hydrogen, alkyl, hydroxyalkyl, allyl, or, when taken together with the nitrogen to which they are attached, comprise a heterocyclic ring radical selected from morpholino or R4-substituted-3-oxo-piperazin-1-yl-wherein R4 is hydrogen, alkyl, or hydroxyalkyl.

6. The compound of Claim 5 which is selected from methyl 2-[N-(2-hydroxyethyl)-N-methyl-aminosulfonyl]-6-nitrobenzoate; methyl 2-[N,N-di(2-hydroxyethyl)aminosulfonyl]-6-nitrobenzoate; methyl 6-nitro-2-[3-oxo-1-piperazinylsulfonyl]benzoate;
methyl 2-[N-morpholinosulfonyl]-6-nitrobenzoate;
methyl 2-[N-(2-hydroxyethyl)aminosulfonyl]-6-nitro-benzoate; N-(2-hydroxyethyl)-2-[N-(2-hydroxyethyl)-aminosulfonyl]nitrobenzamide; allyl 2-[N-morpholino-sulfonyl]-6-nitrobenzoate; N,N-dimethyl-2-[N-(2-hydroxyethyl)aminosulfonyl]-6-nitrobenzamide; N,N-dimethyl-2-[N-(2-hydroxyethyl)-N-methylaminosulfonyl]-6-nitrobenzamide; and N,N- dimethyl-2-[N-(3-hydroxy-propyl)-N-methylaminosulfonyl]-6-nitrobenzamide.

7. A 2-substituted sulfamyl derivative of 6-nitrobenzoic acid ester, or physiologically accept-able salts thereof, of the formula wherein R4 is alkyl, or alkyl substituted with hydroxyl;
R5 is alkyl substituted with ; and R6 is hydrogen, alkyl, or alkyl substituted with hydroxyl, with the proviso that when forms a hetero-cyclic ring, said ring is aziridinyl, azetidinyl, pyrrolidyl or piperidyl.

8. Ethyl 2-[N-(2-dimethylaminoethyl)amino-sulfonyl]-6-nitrobenzoate, its hydrochloride, or physiologically acceptable salts thereof.

9. Methyl 2-[N-(2-dimethylaminoethyl)-N-(2-hydroxyethyl)aminosulfonyl)-6-nitrobenzoate, its hydrochloride, or physiologically acceptable salts thereof.

10. Isopropyl 2-[N-(2-dimethylaminoethyl)-aminosulfonyl]-6-nitrobenzoate, its hydrochloride, or physiologically acceptable salts thereof.