DD156812A1 - METHOD FOR PRODUCING HYDRAZINOHETEROCYCLES - Google Patents

Abstract

The aim of the invention is to develop a process for the preparation of 3-amino-4-aryl-6-hydrazino-7H-pyrazolo & 3,4-b! Pyridines. The hydrazino heterocycles d. general formula III, in which R is an optionally alkyl-, alkoxy- or halogen-substituted phenyl radical, can be prepared by oxidation of the bis (methylthio) pyridinecarbonitriles of the general formula I in which R is as defined above, to the bis (methylsulfonyl) pyridinecarbonitriles of general formula II in which R has the above meaning, and their subsequent reaction with hydrazine hydrate are prepared. These hydrazino heterocycles can be used as organic intermediates for further syntheses. They are particularly suitable for the preparation of further condensed heterocycles.

Description

2282 8 1

Process for the preparation of hydrazino heterocycles Field of application of the invention

The invention relates to a process for the preparation of 3-amino-4-aryl-6-hydrazino-7H-pyrazolo [3,4-t-pyridines. These hydrazino heterocycles can be used as organic intermediates for further syntheses Representation of Further Condensed Heterocycles «,

Characteristic of the known Technical Writer hey ^ solutions

3 ~ ^ ino- ^for t ~ 3 ^ yl 6 - ti-ydrazino-7H ~ pyrazolo jj3,4-bjpyridine are not yet known "

goal of

The aim of the invention is to develop a process for the preparation of these 3-A-2iisio-4-aryl-6-hydrazino-7H-pyrazolo [ß »4-bjpyridine.

Explanation of the We sens the invention

D.ie hydrazinoheterocycles of the general formula III in which E is an optionally alkyl-, alkoxy- or halogen-substituted Baenylrest, by oxidation

in the fen Itä? β »W

the bis-methylthio-1-yridine carbonitriles of the general formula I _? in which R is as defined above, to the bis- (methylsulfonyl) pyridinearonitriles of the general formula H ₅ in which R has the above meaning and whose subsequent reaction with hydrazine hydrate is produced *

The oxidation of bis (methylthio) pyridincarbonitrile of the general formula I is most conveniently carried out with potassium permanganate in glacial acetic acid / water, "For this purpose, the bis (methylthio) pyridincarbonitrile I dissolved in glacial acetic acid in the heat. Are added to this solution, a saturated aqueous potassium permanganate solution with stirring hinzuj until the purple color consist bleibte A discoloration of the reaction mixture is carried out with an aqueous sodium sulfite solution _e This is also the precipitation of the bis (methylsulfonyl) of the general formula II pyridincarbonitrile FULL After filtering and washing with water can be carried out further purification by recrystallization from glacial acetic acid · the reaction which takes place bis (methylsulf onyl) pyridincar-bonitril © II with hydrazine hydrate in organic solvents, preferably in alcohols _s. It is convenient to use the _$ hydrazine hydrate in excess. The reaction temperatures are at the boiling points of the solvent used, "The reaction times are two to eight hours" After cooling the reaction mixture to 15 ⁰ C, the hydrazino heterocycles of the general formula III crystallize in excellent purity,

embodiments

Embodiment 1

2,6-bis (methylsulfonyl) -4-phenyl-pyridine-3-carbonitrile

0.005 mol of 2,6-bis (methylthio) -4-phenyl-pyridine-3-carbonitrile are dissolved in 50 ml of hot glacial acetic acid. Man ver. added with stirring in portions with a saturated

228261 2

aqueous solution of potassium permanganate until the violet color persists. A precipitate of crystals precipitates out. The reaction mixture is decolorized by addition of an aqueous sodium sulfite solution. The precipitate is filtered off, washed with water and crystallized from glacial acetic acid,

Yield? 77.4% of theory Melting point: 243-247 ° C

O ₁₄ H ₁₂ I ₂ O ₄ S ₂ (336.4)

Ber. O 49.99 H 3.59 H. 8.25 Gef. O 50.21 H 3.65 N 8.50

Embodiment 2

4 ~ (p-bromo-phenyl) -2,6-bis (methylsulfonyl) -pyridine-3-carbonitrile

0.005 mol. 4- (p-Bromophenyl) -2,6-bis (methylthib) -pyridine-3-carbonitrile are reacted with aqueous potassium permanganate solution as described in Example 1. , ,

Yield 93.4% of theory Melting point 219-223 ° C

C ₁₄ H ₁₁ BrN ₂ O ₄ S ₂ (415.3)

Ber · C 40.48 H 2.66 N 6.74

Gef * C 40.72 H 2.61 N 6.78

Embodiment 3

4- (p-chloro-phenyl) -2,6-bis (methylsulfonyl) -pyridine-3-carbonitrile

0.005 mol of 4- (p-chlorophenyl) -> 2,6-bis (methylthio) -pyridine-3-carbonitrile are reacted with aqueous EaIiumpermanganatlösung, as described in Example 1

Yield: 93% of theory , Melting point i 189-191 ⁰ C

C ₁₄ H ₁₁ ClS ₂ O ₄ S ₂ (370.8)

Ber "O 45.34 H 2.98 K 7.55 Gefe O 45.51 H 3.12 N 7.84

Embodiment 4

3-amino-6-liydrazino-4-phenyl-7H-pyrazolo [3,4-b] pyridine

0.005 sol 2,6-Bts (met1-iylsulfonyl) -4- "p] -ienyl-pyridiii-> 3-carbonitrile are refluxed in 1 ml of ethanol with 0.02 mol of 85% hydrazine hydrate for 4 hours." The mixture is allowed to stand Cool to 15 ^° C., filter and wash with ethanol.

Ausbeutes 91 "5% d _e Tfcu melting point 216-18 ⁰ C.

C ₁₂ H ₁₂ N ₆ (240.3)

Ber. C 59.98 H 5.03 N 34.98 Gef. C 59.64 H 5.21 N 34.64

3-Amino-4- (p-bromo-phenyl) -6-hydrazino-7H-pyrazolo [3 $ ^ - ^ J pyridine

0.005 mol of 4- (p-bromo-phenyl) -2,6-bis (methylsulfonyl) -pyridine-cis-oxy-titanium are mixed with 0.02 mol of 85% strength Hy. reacted drazinhydrat, as in embodiment 4

"described,.

Yield: 45% of theory , Melting point of 283-285 ° C

(319,2) Ber _e N 26,33

Gef * N 26.04

Claims (1)

"'" 2282 61 2 invention claim Process for the preparation of hydrazino heterocycles. of the general formula III, in which R is an optionally alkyl-, alkoxy- or halogen-substituted benzenyl radical, characterized in that bis (methylthio) pyridinecarbonitriles of the general formula I in which R is as defined above »to form bis (methylsulfonyl) - Pyridincarbonitrilen of the general formula II, in which R has the above meaning, oxidized and. These are subsequently reacted with hydrazine Hyarat » For this 1 page drawings