Patent GB-1315524-A (GB)
Title: 2-trifluoromethyl-quinoxaline-di-n-oxides
IPC: C07D241/52
Filed: 1970-05-05
Abstract: 1315524 Trifluoromethyl-quinoxaline-di-N- oxides PFIZER Inc 5 May 1970 [5 Feb 1970] 21671/70 Headings C2C and C2P Novel quinoxaline-di-N-oxides having the formulae wherein X is in the 6- or 7-position and is H, Cl, F, CH 3 , CH 3 O, CF 3 , SO 2 NH 2 , SO 2 NH(CH 3 ) or SO 2 N(CH 3 ) 2 ; Z is H, COOH, -COOC 1-4  alkyl, CONH 2 , Cl, F, Br, -SC 1-4  alkyl, -SOC 1-4  alkyl, -SO 2 C 1-4  alkyl, OH, -O-C 1-4  alkyl, -O.CO-C 1-3  alkyl, -NH 2 , -NHR<SP>1</SP> or -NR<SP>1</SP> 2  (where R<SP>1</SP> is C 1-4  alkyl), -N(CH 3 ) 3  or -ONO 2 ; R 1  is H or C 1-4  alkyl; R is H, -CO.O.C 1-4  alkyl, CONH 2 , Cl, Br, F, CN, -O-C 1-4  alkyl, -S-C 1-4  alkyl, -SOC 1-4  alkyl, -SO 2 C 1-4  alkyl, -NH 2 , -NHR<SP>1</SP> or -NR<SP>1</SP> 2  (where R<SP>1</SP> is C 1-4  alkyl), w,w,w-trifluoro C 1-4  alkyl, CF 3 CO, phenyl, cycloalkyl, di-(C 1-4  alkyl)N.CH 2 CH 2 -, -COR 2 , -CHO or -CH=N-R 5 , wherein R 5  is NHCONH 2 , NHCSNH 2 , NHC(NH)NH 2 , NHR 6 , NHCOOR 7 , NHCOR 8 , OR 9 , where R 6  is C 1-4  alkyl, benzyl, or C 2-4  hydroxyalkyl; R 7  is C 1-4  alkyl or C 2-4  hydroxyalkyl; R 8  is C 1-4  alkyl or phenyl; and R 9  is H or C 1-4  alkyl; and R 2  is C 1-4  alkyl, phenyl, 2-furyl, 2- pyrrolyl, 2-thienyl, 2,5-dimethyl-3-thienyl or 5-substituted-2-thienyl wherein the substituent is CH 3 , Cl, Br or I; the non-toxic acid addition salts of the amino compounds; and the Na and K salts of those compounds where Z is -COOH; may be obtained by reacting the appropriate benzofuroxan with a compound of Formula (IV) CF 3 COCH 2 R 4 , (V) CF 3 COCH 2 COR 2  or (VI) CF 3 CH 2 COR 3 , wherein R 4  is -CONH 2 , -CO.O.C 1-4  alkyl, HO-C 1-4  alkyl, CF 3 CO, phenyl, cycloalkyl, C 1-4  alkyl, -S-C 1-4  alkyl, -OC 1-4  alkyl (C 1-4  alkyl) 2 N-, w,w,w-trifluoro- C 1-4  alkyl, or -CH(Z)R<SP>1</SP> 4  where Z is -COO- alkoxy, -COOH or -CONH 2 , and R<SP>1</SP> 4  is C 1-4  alkyl; R 3  is C 1-4  alkyl or phenyl. Compounds wherein R is alkylthio can be oxidized to the corresponding sulphinyl or sulphonyl compounds and hence converted to the 3-halo compounds. The latter can be converted to compounds wherein R is CN, amino or alkoxy. Similarly the 3-halo-alkyl compounds are converted by standard procedures into compounds in which Z is CN, amino, (CH 3 ) 3 N, OH, alkoxy, alkanoyoxy and nitrate ester. Intermediate ketones of the formula where R<SP>1</SP> is CH 3 , C 2 H 5 , n or i-C 3 H 7 , or n or sec- C 4 H 9 , are obtained by reacting the corresponding R<SP>1</SP>SH with CF 3 COCH 2 Cl; similar ketones CF 3 COCH 2 OR<SP>1</SP> are obtained from R<SP>1</SP>OH and CF 3 COCH 2 Cl; corresponding amino ketones CF 3 COCH 2 NR<SP>1</SP>R<SP>11</SP> are obtained by a similar method; aminoketones of formula are obtained from CF 3 COCH 2 COOC 2 H 5  and ClCH 2 CH 2 NR<SP>1</SP>R<SP>11</SP>. Ethyl trifluoroacetylacetate is prepared from carbethoxymethyltriphenylphosphonium bromide by the following reaction scheme the phosphorane compound of Formula III being isolated before the final treatment with zinc dust and acetic acid. In a similar manner the compounds of formula where R<SP>11</SP> is -COOR<SP>111</SP> (R<SP>111</SP> is n- and i-propyl and n-butyl), -CH 2 CONH 2 , -CH 2 COOCH 3  and -CH 2 COO(n-C 4 H 9 ) are prepared by the above procedure from the appropriate triphenyl phosphonium bromides [(C 6 H 5 ) 3 PCH 2 R<SP>11</SP>]Br where R<SP>11</SP> has the above significance, which are obtainable by reacting triphenylphosphine and R<SP>11</SP>CH 2 Br, via the corresponding phosphoranes. Esters of formula are prepared by the following reaction scheme the phosphorane compound of Formula III being isolated before the treatment with zinc and acetic acid. The corresponding amides are prepared from the esters by heating with ammonium and evaporating to dryness.