Benzoylation of Amines sans Alkali: A Green Protocol in Neat Phase

Table 1

Results of benzoylation of amines in neat phase (solvent-free condition) sans base^#.

Entry	Substrate	Product	Yield^a (%)	mp^oC (lit. [31] mp^oC)	Time (min)
1	Aniline	Benzanilide	92	164 (163)	3
2	2-Methylaniline	2-Methylbenzanilide	76	142 (143)	3
3	3-Methylaniline	3-Methylbenzanilide	91	125 (125)	3
4	4-Methylaniline	4-Methylbenzanilide	89	157 (158)	3
5	2-Chloroaniline	2-Chlorobenzanilide	95	99 (100)	3
6	3-Chloroaniline	3-Chlorobenzanilide	76	121 (120)	3
7	4-Chloroaniline	4-Chlorobenzanilide	95	191 (192)	3
8	3-Nitroaniline	3-Nitrobenzanilide	69	156 (155)	10
9	4-Methoxyaniline	4-Methoxybenzanilide	92	153–54 (154)	5
10	2-Aminobenzoic acid	2-(N-benzamido) benzoic acid	76	180 (182)	5
11	4-Aminobenzoic acid	4-(N-benzamido) benzoic acid	73	>250 (278)	5
12	Methyl anthranilate	N-benzoyl methylanthranilate	76	98-99 (100)	5
13	1-Naphthyl amine	1-N-benzamido-naphthalene	66	159 (161)	3
14	4-Amino pyridine	N-(4-pyridyl) benzamide	66	208–209	20
15	2-Amino thiazole	N-(2-thiazolyl) benzamide	70	150 (152^[30])	10
16	Benzyl amine	N-benzyl benzamide	88	105 (106)	3
17	Cyclohexyl amine	N-cyclohexyl benzamide	86	147–48 (148)	2
18	N,N-dimethyl hydrazine	N,N-dimethyl benzamide	75	166–67	10
19	Diphenyl amine	N-benzoyl diphenyl amine	67	180 (182)	25
20	Morpholine	N-benzoyl morpholine	58	73 (75)	20

^#All the compounds give satisfactory spectral data (IR, NMR).
^aYield refers to the combined amounts of the first and second crop of crystallized product.