| 摘要 |
This invention provides processes for preparing 4-(monoalkylamino)benzoic acids and esters which are useful as hypolipidemic and antiatherosclerotic agents and particularly a process for preparing <IMAGE> wherein n is 12 to 17 and A is hydrogen, lower alkyl or alkali metal; by reacting <IMAGE> wherein R1 is hydrogen or H(CH2)p-W- (CH2)q- in which p and q are from 0 to 17 selected such that the total of C atoms in R1 is n+1 and W represents one or more of <IMAGE> with X being halogen, hydroxy, sulfonyloxy, mercapto, loweralkylthio, arylthio, disulfido, loweracylthio, loweralkylsulfinyl, arylsulfinyl, loweralkylsulfonyl, arylsulfonyl, sulfo, or sulfamyl, with Z being oxygen or sulfur and R being aryl, loweralkyl or alkylene group; R2 represents a chemical bond to another structure II or to amino moieties or is hydrogen, hydroxy, alkoxy, loweralkanoyl, aroyl, loweralkoxycarbonyl, arylalkoxycarbonyl, loweralkylsulfonyl, arylsulfonyl, aroylmethylsulfonyl, trifluoroacetyl; R3 represents one or more of hydrogen, halo, mercapto, loweralkylthio, arylthio, acylthio, disulfido, alkyl- or arylsulfonyl or sulfinyl, sulfamyl, thiocyanato, sulfo, carboxy or when taken together with NR2 represents a fused thiazolo ring; and R4 is CO2A or methyl, phenoxycarbonyl, substituted-alkylcarbonyl, carbamoyl, 2-oxazolinyl, cyano, formyl, hydroxymethyl, triloweralkoxymethyl, diloweralkoxymethyl, bromo or lithio therefrom, trimethylsilyl or loweralkoxycarbonylacetyl; either with hydrogen metal catalyst, Raney nickel, sodium borohydride, sodium cyanoborohydride +/- p- toluenesulfonylhydrazide, sodium in ethanol, diborane, amalgamated zinc/ HCl or hydrazine and potassium hydroxide; or when R1, R2 and R3 are hydrogen with CH3(CH2)n-1CN, <IMAGE> CH3(CH2)n-1CO2H, or H(CH2)PCH=CH(CH2)q-1CHO in the presence of hydrogen and a metal catalyst or hydride; with the proviso that W may be -CH2- when R4 is other than -CO2A in which case II is converted to I by reaction with potassium permanganate, chromium trioxide, mineral acid, alkali metal hydroxide, oxalyl chloride in the presence of aluminum chloride, or carbon dioxide, further processes for preparing compounds I are also provided. |
