Ammonium Trifluoroacetate-Mediated Synthesis of 3,4-dihydropyrimidin-2(1H)-ones

Table 1

General synthesis of ammonium trifluoroacetate-mediated dihydropyrimidines.

Compound	Ar	R1	X	Time (min)	Yield (%)^a,b	Mp (°C)
4a	Phenyl	CH3	O	10	98	200–202
4b	3-Methoxy phenyl	CH3	O	12	95	224-225
4c	3-Carboxyphenyl	CH3	O	15	90	291–293
4d	3-Nitrophenyl	CH3	O	10	85	231–233
4e	Phenyl	H	O	10	92	190-191
4f	Phenyl	CH3	S	20	83	209–211
4g	3-Cyanophenyl	CH3	O	25	78	236-237
4h	3-Methyl phenyl	CH3	O	20	95	233-234
4i	2-Fluorophenyl	CH3	O	18	70	235-236
4j	4-Chlorophenyl	H	S	15	75	138-139
4k	2-Naphthyl	CH3	O	10	90	210–212
4l	Benzyl	CH3	O	20	85	176–178
4m	2-Hydroxy-5-methoxy phenyl	CH3	O	28	73	241-242
4n	2-Hydroxy-5-iodophenyl	CH3	O	60	55	170-171
4o	2-Hydroxy-5-t-butyl phenyl	CH3	O	8	70	220–222
4p	2-Hydroxy-5-nitrophenyl	H	S	18	82	181-182
4q	3,5-Bis-trifluoromethyl phenyl	CH3	O	35	60	209-210
4r	2,3-Dichlorophenyl	H	S	18	70	182–184
4s	2-Thienyl	CH3	O	12	78	206–208
4t	3-Thienyl	CH3	O	15	70	234-235
4u	2-Pyridyl	CH3	O	25	85	183–185
4v	3-Furyl	CH3	O	20	45	206-207
4w	2-Thiazolyl	CH3	O	20	60	215-216
4x	4-Thiazolyl	H	S	15	55	270–273
4y	2-Imidazolyl	CH3	O	30	35	258–260
4z	1-Methyl-indol-3-yl	CH3	O	40	50	199–201

^aIsolated yield.
^bAll the target molecules were characterized with IR, LCMS, ¹H NMR, and ¹³C NMR.