Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1999-05-03
2000-04-04
Geist, Gary
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
548206, C07D27504
Patent
active
060463392
DESCRIPTION:
BRIEF SUMMARY
This application is the national phase of PCT/EP97/05972 filed Oct. 29, 1997.
The present invention relates to a process for the production of 1,8-naphthosultam.
Various procedures are already known for the production of 1,8-naphthosultam. For example, in Russian Patent No. 379576, 1,8-naphthosultam is produced by the dehydration of 1-naphthylamine-8-sulfonic acid using POCl.sub.3 or PCl.sub.3 in nitrobenzene at 140.degree.-150.degree. C., the characteristic feature of the process being that the dehydration is conducted in the presence of calcined potash. Russian Patent No. 1397441 describes the production of 1,8-naphthosultam by reacting 1-naphthylamine-8-sulfonic acid with POCl.sub.3 in chlorobenzene at 110.degree.-125.degree. C. in the presence of a pyridine compound. Further, Russian Patent No. 614104 describes the production of 1,8-naphthosultam by dehydrating 1-naphthylamine-8-sulfonic acid with POl.sub.3 in chlorobenzene at 130.degree. C. in the presence of the disodium salt of 1,1'-dinaphthylmethane-6,7'-disulfonic acid, as dispersant.
Each of these known processes, however, suffers from one or more disadvantages, in particular the need to use high reaction temperatures and/or the use of a reaction solvent or proton acceptor which is hazardous, from the handling, safety or toxicological standpoint, when used in large-scale production processes. Undesired side-reactions, in particular the formation of polymeric sulfonamides, may also be observed in the known processes.
The object of the present invention is to provide a new process for the production of 1,8-naphthosultam which is free from the disadvantages associated with prior processes.
Accordingly, the present invention provides a process for the production of 1,8-naphthosultam comprising reacting 1-naphthylamine-8-sulfonic acid with excess POCl.sub.3 or PCl.sub.3 in the presence, as proton acceptor, of a mono-, di- or, preferably, tri-C.sub.1 -C.sub.4 alkylamine, and in the presence, as reaction solvent, of a mono-, di-or tri-C.sub.1 -C.sub.4 alkylbenzene.
POCl.sub.3 is preferably used as the dehydrating agent for 1-naphthylamine-8-sulfonic acid.
The proton acceptor used according to the process of the present invention may be a mono-C.sub.1 -C.sub.4 alkylamine, such as methylamine, ethylamine, n-propylamine or n-butylamine. Di-C.sub.1 -C.sub.4 alkylamines, e.g., dimethylamine, diethylamine, di-n-propylamine or di-n-butylamine, may also be used. It is preferred, however, to use a tri-C.sub.1 -C.sub.4 alkylamine, such as trimethylamine, tri-n-propylamine, tri-n-butylamine or, especially, triethylamine, as the proton acceptor.
As a mono-C.sub.1 -C.sub.4 alkylbenzene solvent in the process of the present invention, there may be used, e.g., toluene, ethylbenzene, n-propylbenzene, isopropylbenzene or t-butylbenzene. Di-C.sub.1 -C.sub.4 alkylbenzenes, e.g., xylenes, diethylbenzenes, di-n-propylbenzenes or di-n-butylbenzenes, may also be used. Tri-C.sub.1 -C.sub.4 alkylbenzenes include, e.g., mesitylene. The preferred solvents are toluene and, especially, mesitylene.
The process according to the present invention is conveniently conducted by dissolving 1-naphthylamine-8-sulfonic acid in the reaction solvent and then reacting the 1-naphthylamine-8-sulfonic acid, in the presence of a proton acceptor, with excess POCl.sub.3 or PCl.sub.3 at an elevated temperature. Unreacted POCl.sub.3 or PCl.sub.3 is conveniently hydrolysed to phosphoric acid by adding an aqueous medium, such as ice-water or dilute aqueous sodium hydroxide solution. The precipitated crude 1,8-naphthosultam so obtained may then be separated by filtration and dried. If desired the crude 1,8-naphthosultam may be purified by recrystallisation from a suitable solvent, e.g. toluene.
In an alternative reaction sequence, the POCl.sub.3 or PCl.sub.3 may be first dissolved in the reaction solvent and, to this solution, there may then be added a suspension of the 1-naphthylamine-8-sulfonic acid in the reaction solvent, in the presence of a proton acceptor, and the reaction mixture may be worked up
REFERENCES:
J Phys Chem "Multiple Fluorescences. 6. The Case of 1,8-Naphthosultam" by Kosower vol. 86 pp. 3776-3780, 1982.
J Org Chem "The Pyrolysis of 2H-Naphth[1,8-cd]isothiazole 1,1-dioxide and its 2-Phenyl Analog" by De Jongh vol. 37, No. 13 pp. 2152-2152, 1972.
CA:89 129502 abs of SU 614104, Jul. 1978.
Chem. Abstr. vol. 1, No. 23, 2884, for J. Am. Chem. Soc., Vol. 29, pp. 1319-1328 (1907).
Derwent Abstr. 88-351877 for SU 1397441 (1988).
Derwent Abstr. 73-80309u for SU 379576 (1973).
Ciba Specialty Chemicals Corporation
Geist Gary
Mansfield Kevin T.
Vollano Jean F
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