SYNTHESIS AND PROPERTIES OF 1-ALKOXYCARBONYL METHY- 2-ALKYLPYRROLES

The condensation of alkyl 2,3-dichloropropyl- and alkyl 2-methoxy-3-chloropropyl ketones with aminoacetic acid alkyl ester hydrochlorides leads to 1-alkoxycarbonylmethyl-2-alkylpyrroles. The reaction of these esters with various bases gives the corresponding 1-carbonylmethyI-2-alkylpyrroIes, 78%, respectively. In the case of the benzyl amine and the corresponding esters 11I and IV, a temperature of 50-55~ over 5 h gives the 1-benzylaminocarbonyimethyl-2-alkylpyrroles (Via, VId) in yields of 74 and 65 %. In order to complete the reaction of lIIb, Hid, Iva, and IVc with secondary amines it is necessary to keep the reaction mixture at 75-80~ for 8 h, which leads to yields of 65-82% for the 1-diethylamino- (VIIa and Vrlc), 1-piperidino- (Villa and VIIIc) and 1-morpholinocarbonylmethyl-2- alkylpyrroles (IXb and IXd). The 1-carbazoylmethyl-2-alkylpyrroles (Xb m'ld Xc) were synthesized in yields of 75 and 71%, respectively, by boiling the esters )lib or lllc for 6 h in alcohol with a small excess of hydrazine hydrate. Keeping an equimolar amount of IVb and 1Ve in an alcoholic solution of potassium hydroxide for 6 h at a temperature of 55-60~ gave the potassium salts of 2-alkylpyrrolyl-l-acetic acid (XIb and XIe) in yields of 85 and 78%. The treatment of salt Xlb in 10% aqueous HC1 solution produced the corresponding 2-alkyl-N-pyrrolylacetic acid (XIIb). The characteristics of the synthesized compounds are presented in Table 1. The structures of the substituted pyrroles III-XII were conftrmed by IR and 1H NMR spectra. Thus, the IR spectra of these compounds showed characteristic absorption bands for the pyrrole ring at 3090-3144 (U=C-H), 1485-1556 (nucleus Uc=c) , 718-780 cm -1 (nucleus 6=c_n), and also characteristic absorption bands for the functional groups: 3280-3310 (UN_H), 1730-1750 (UC=O), 1616-1672 (PC=O, amide I), 1540-1637 (6N-H ~ C-N amide II), 1195-1210 cm -1 (Uc_o_c), which correspond with literature data (7).