Patent GB-1187991-A (GB)
Title: Process for the production of Quinoxaline-Di-N-Oxides
Inventor: LEY KURT
IPC: C07D241/52
Filed: 1967-05-04
Abstract: 1,187,991. Quinoxaline di-N-oxides. FARBENFABRIKEN BAYER A.G. 4 May, 1967 [4 May, 1966; 12 Jan., 1967; 10 Aug., 1967], No. 20842/67. Headings C2C and C2U. [Also in Division C4] The invention comprises a general method of preparing quinoxaline 1,4-di-N-oxides in which a benzofurazane of the formula wherein x is 1 or 2 and R represents hydrogen, halogen or an alkyl, alkoxy, carbalkoxy or carbaryloxy group or the radical -X-NYZ in which X is -SO 2 - or -CO-, Y is hydrogen or an alkyl group and Z is (1) hydrogen; (2) an alkyl group; (3) a cycloalkyl group having 5-8 carbon atoms in the ring; (4) an aryl group optionally substituted by 1-3 C 1-6  alkyl or alkoxy groups or by halogen; or (5) a heterocyclic radical, or Y and Z together complete a heterocyclic ring, is reacted at 20-100‹ C. in an organic diluent, with at least an equimolar amount of both a compound which contains a ketonic or aldehydic carbonyl group and which has a methylene or methyl group adjacent to the carbonyl group, and of ammonia or a primary aliphatic or cycloaliphatic amine, or with at least an equimolar amount of the corresponding Schiff's base, and quinoxaline di-N- oxides of the Formulµ II, III and V wherein in Formula II R 1  represents (1) a C 1-18  alkyl group optionally substituted by a cyano, oximino, phenyl or amino group -NR 3 R 4  (in which R 3  and R 4  are C 1-6  alkyl groups or together form a 5- or 6-membered heterocyclic ring which may also contain O or S as hetero atoms); (2) an aliphatic acyl radical having at least 2 carbon atoms; or (3) a benzoyl radical; R 2  represents (A) a C 1-18  alkyl group or (B) the radical -(CH 2 ) y CO.X in which y is 0 or 1 and X represents (a) a C 1-6  alkoxy group; (b) a phenoxy group; (c) a 5- or 6-membered cycloalkoxy group; or (d) the radical -NR 5 R 6  in which (i) R 5  and R 6  are hydrogen or C 1-18  alkyl groups; (ii) R 5  and R 6  together form a 5- or 6-membered heterocyclic ring which may contain a further hetero N, O or S atom para to the N atom; (iii) one of R 5  and R 6  is hydrogen and the other is optionally substituted phenyl or naphthyl which may be fused to a 5- or 6-membered heterocyclic ring containing up to 3 N atoms; (iv) one of R 5  and R 6  is hydrogen and the other is a 5- or 6-membered heterocyclic radical which contains up to 2 N atoms, one N, one O and one S atom, or one O or S atom, and may be fused to a benzene ring; (v) one of R 5  and R 6  is hydrogen and the other a benzene sulphonyl radical optionally substituted by C 1-6  alkyl; or (vi) R 5  and R 6  together form a radical of the formula in which Z is a -CO- or -H 2 CO- radical, or R 1  and R 2  together form a 6-membered cycloaliphatic ring, optionally substituted by an oximino group, which may be fused to another 6- membered cycloaliphatic ring, or a saturated 10- membered cycloaliphatic ring, optionally substituted by an oximino group provided that when X is 1 or 2 and R is hydrogen or an alkyl group and R 1  is a C 1-10  alkyl group, R 1  is substituted, and when X is 1 and R is alkoxy or halogen and R 1  is a C 1-4  alkyl group, R 1  is substituted, and, in Formula III, A represents (i) a C 4-16  straight- or branched-chain aliphatic group optionally substituted by 1 or 2 hydroxy groups, halogen or an aryl group which may in turn be substituted by 1 or 2 alkyl or alkoxy groups, which aliphatic group may contain up to 2 double or triple bonds, provided that if R represents hydrogen or C 1-6  alkyl and contains 5-11 carbon atoms, A must either be substituted or contain a double or single bond; (ii) an aryl group containing up to 14 carbon atoms and optionally up to 3 substituents; (iii) a cycloaliphatic group containing 3-12 ring members; or (iv) a 5- or 6- membered heterocyclic ring, and, in the steroids of the Formula V, W is hydrogen, halogen or a C 1-4  alkoxy radical. The invention is illustrated by numerous examples of the general process and of the novel quinoxaline di-N-oxides. Examples 63-65 relate to the preparation of steroids of the Formula V.