Patent GB-496258-A (GB)
Title: Manufacture of picryl compounds and conversion products thereof
IPC: C07D471/04
Filed: 1937-07-03
Abstract: Picrylamino compounds are prepared by condensing picryl chloride or an alkyl derivative thereof with a compound containing a tertiary cyclic nitrogen atom and an adjacent amino group, e.g. 2-aminopyridine, 2-aminoquinoline, 1 - aminoquinoline, 9 - aminophenanthridine and their homologues.  Alkyl derivatives of picryl chloride mentioned are methyl- and dimethyl-picryl chlorides, obtainable from m-cresol and m-5-xylenol respectively. By cautious heating ring closure takes place with formation of dinitro-1 : 3-diazalines, from which 1 : 3-diazalines may be obtained by reduction and elimination of the amino groups formed. The ring closure is preferably effected in presence of a substance such as phenol or dimethylaniline having an affinity for the nitrous acid split off.  The products are useful as intermediates for the manufacture of dyes and drugs.  According to the examples: (1) picryl chloride is heated in benzene solution with 2 aminopyridine to give N-picryl-2-aminopyridine; when toluene is used as a solvent, ring closure takes place with formation of 1 : 2-pyrido-7 : 9-dinitro-4 : 5-benz-1 : 3-diazaline; (2) the same diazaline product is also obtained by heating the N-picryl-2-aminopyridine in dimethylaniline or in a mixture of nitrobenzene with dimethylaniline or phenol; (3) by heating the diazaline product with an aqueous solution of sodium polysulphide, 1 : 2-pyrido-7 : 9- or 9 : 7-nitroamino-4 : 5-benz-1 : 3-diazaline is produced; when using hydrogen as the reducing agent under an initial pressure of 5 atmospheres and in the presence of platinic oxide, 1 : 2-pyrido-7 : 9-diamino 4 : 5-benz-1 : 3-diazaline is formed, whilst at hydrogen pressures maintained between 8 and 10 atmospheres, tetrahydro-1 : 2-pyrido-7 : 9-diamino-4 : 5-benz-1 : 3-diazaline results; (4) 1 : 2-pyrido-7 : 9- or 9 : 7-nitroamino-4 : 5-benz-1 : 3-diazaline is converted by diazotization and heat treatment with alcohol into 1 : 2-pyrido-7 (or 9)-nitro-4 : 5-benz-1 : 3-diazaline, which may then be reduced catalytically with hydrogen at an initial pressure of 5 atmospheres to 1 : 2-pyrido-7 (or 9)-amino-4 : 5-benz-1 : 3-diazaline; the latter on diazotization and decomposition with alcohol yields 1 : 2-pyrido-4 : 5-benz-1 : 3-diazaline, which is isomeric with a -carboline; (5) picryl chloride is condensed as in (1) with 2-amino-3-methylpyridine to form either the picrylamino compound or 31 - methyl - 1 : 2-pyrido-7 : 9-dinitro-4 : 5-benz-1 : 3-diazaline; the picrylamino compound can be converted into the diazaline by heating in phenol and xylene; catalytic reduction of the diazaline using hydrogen under an initial pressure of 5 atmospheres and in presence of platinic oxide produces the diamine, whose bis-diazonium salt decomposes to 31-methyl-1 : 2-pyrido-4 : 5-benz-1 : 3-diazaline; (6) picryl chloride is condensed with 2-aminoquinoline or 1-aminoisoquinoline in benzene solution to give the picrylamino compounds, which yield the corresponding dinitrodiazalines on heating with phenol in xylene; treatment with hydrogen under a pressure of 31 atmospheres in the presence of platinic oxide gives rise to the respective diaminodiazalines, viz.: 1 : 2-quinolo or isoquinolo-7 : 9-diamino-4 : 5-benz-1 : 3-diazaline; elimination of the amino groups from these diazalines by the diazo reaction results in the formation of 1 : 2-quinolo or isoquinolo-4 : 5-benz-1 : 3-diazaline, the former being isomeric with quinindoline; (7) picryl chloride is condensed with 9-aminophenanthridine in xylene and the picrylamino product heated with dimethylaniline to form the dinitrodiazaline.  Specification 461,185 is referred to.