SE437985B - NEW N-METOXICARBONYL-N? 721-SUBSTITUTED HYDRAZINE USED AS AN INTERMEDIATE FOR THE PREPARATION OF METHYL-3- (2-CHINOXALINYLMETHYL) -CARBAZATE-N? 721, N? 724-DI - Google Patents

Description

80033934-2 for the preparation of methyl 3- (2-quinoxalinylmethylene) -carbazate--N1, N4-dioxide having the formula: O + N, cH = NNHcoocH I N '/ <3 í:; ::] :: ï ïlt + o 4 which is characterized in that a 2-halomethylquinoxaline-N1, N - -dioxide of the formula: II CH X O4-Z wherein X is chlorine or bromine, is reacted with one to two equivalents of an alkali metal carbonate and one more two equivalents of a hydrazine having the formula: R "NHNHCOOCH3" III wherein R "represents cF3so2, tcF3cH2so2, cH3so2 or CH CH SOO, in a reaction-inert solvent at a temperature from 75 to 85 C, after which the desired carbazate of formula I is recovered.

The above process, which comprises reacting a 2-halomethylquinoxaline-N1, N4 dioxide in a reaction inert solvent in the presence of an alkali metal carbonate, e.g. anhydrous potassium carbonate, with an alkyl- or arylsulfonyl-substituted hydrazine, e.g. N-methoxycarbonyl-N'-triphyl-hydrazine, can be represented by the following reaction scheme: âuuaasa-9 3 o cF o + | 3 + N SO 2 N / \ »Im K2C ° 3 \ + J / -____;> // N f NH N + C fl zx | In a preferred embodiment of the process, a 2-halomethylquinoxaline, N4 dioxide, preferably 2-bromomethylquinoxaline compound, is heated to a temperature of 75-85 ° C in a reaction-inert solvent such as acetonitrile with one to two equivalents of N-methoxycarbonyl-N'-triphylhydrazine in the presence of one to two equivalents of anhydrous potassium carbonate, until the reaction is substantially complete (about 1-2 hours). Preferably the reaction is carried out with an equimolar amount of potassium carbonate and N-methoxycarbonyl-N'-triphylhydrazine.

The 2-halomethylquinoxaline derivatives used in the above process are prepared more readily and more economically than the corresponding 2-bis (halo) methylquinoxaline compounds described in U.S. Pat. No. 3,839,326.

The 2-halomethylquinoxaline intermediates used in the above process can be prepared according to the general methods described in U.S. Pat. No. 3,753,987, J. Chem. Soc., 2052 (1956) and Chemistry of Heterocyclic Compounds, 940 (1967). The halogen can be chlorine or bromine.

The preferred intermediates are the 2-bromomethylquinoxaline compounds. These compounds are prepared from 2-methylquinoxaline-1,4-dioxides according to the methods described in J. Chem. Soc., 322 (1943), U.S. Pat. Nos. 3,474,097, 3,553,208, 3,660,398 and British Pat. No. 1,215,815.

N-methoxycarbonyl-N'-triphylhydrazine, N-methoxycarbonyl-N'-triazol-2-sylhydrazine, N-methoxycarbonyl-N'-methanesulfonylhydrazine and N-methoxycarbonyl-N'-tosylhydrazine can be prepared according to the general procedure described and J. Org. Chem., Vol., 3450 (1975). For example, N-methoxycarbonyl-N'-triphylhydrazine can be prepared by adding a solution of triflic acid anhydride in methylene chloride dropwise to a methylene chloride solution containing an equimolar amount of methyl carbazate and a slight molar excess of triethylamine. The resulting mixture is allowed to warm to room temperature and stirred for about 16 hours. The mixture is concentrated in vacuo at room temperature and the residue is then extracted with several portions of ether. The ether extract is concentrated in vacuo at room temperature to a waxy solid, which is used directly in the subsequent reaction without further purification. Alternatively, the omission of triethylamine and the use of two equivalents of methyl carbazate give the crystalline product.

N-methoxycarbonyl-N'-triphylhydrazine and N-methoxycarbonyl-N'-tresylhydrazine are novel compounds and consequently the invention provides a novel N-methoxycarbonyl-N'-substituted hydrazine which is useful as an intermediate in the preparation of of the compound of formula I above, which is characterized in that it has the formula: R "NHNHCOOCH III 3 wherein R" is CF 3 SO 2.

The following examples illustrate the preparation of the new intermediate according to the invention.

Example 1

N-methoxycarbonyl-N'-triphylhydrazine. 4 mmol of triflic acid anhydride in 40 ml of methylene chloride were added dropwise to a solution of 35.5 mmol of methyl carbazate and 38.9 mmol of triethylamine in 200 ml of methylene chloride at -78 ° C with stirring. The resulting mixture was allowed to warm to room temperature under vacuum and the residue was extracted with aoozsez-9 3 x 100 ml refluxed ether. The combined ether extract was concentrated in vacuo at room temperature to give a waxy solid (5.26 g, about 67%).

The NMR spectrum of the crude product confirmed the expected product, contaminated with the triethylamine salt of triflic acid.

The crude material was used directly without further purification in subsequent reactions. 336 mmol of methyl carbazate was added with stirring for 20 minutes to a solution of 178 mmol of triflic acid anhydride in 2000 ml of methylene chloride under a nitrogen atmosphere at ~ 78 ° C. The resulting solution was allowed to warm to room temperature and stirred for 20 hours. The resulting thick white suspension was concentrated in vacuo at room temperature to give a white solid. This material was triturated with 450 ml of diethyl ether and collected to give the methyl carbazate salt of triflic acid. The diethyl ether filtrate was concentrated in vacuo at room temperature to give a white solid, which was triturated with hexane and collected, washed with hexane and dried to give the product as a white crystalline substance (yield 84%), m.p. 107 DEG-109 DEG.

C 3 H 5 O 4 N 2 F 3 S: Calculated: C 16.21 H 2.25 N 12.61% Found: C 16.24 H 2.20 N 12.68%. : w-. fl- w- »p-o ~ _ _ _, U -... mw-H-e-w - ~. ._., ._ _

Claims (1)

A new N-methoxycarbonyl-N'-substituted hydrazine, which is useful as an intermediate in the preparation of methyl -3- (2-quinoxalinylmethylene) -carbazate-N1, N4-dioxide, having the formula: H-NNHCOOCH3 N + O ... It is characterized in that it has the formula: R "NHNHCOOCH3 III wherein R" is CF3SO2-