An Expeditious and Safe Synthesis of Some Exocyclic α,β-Unsaturated Ketones by Microwave-Assisted Condensation of Cyclic Ketones with Aromatic Aldehydes over Anhydrous Potassium Carbonate

Table 1

Microwave-assisted condensation of chromanones/1-tetralone/1-indanone with aromatic aldehydes.

Entry	Ketone (1)	Ar of aldehyde	Time (min)	Product (2)	Yield (%)	M.P. (°C); Obs. (Lit.) [Reference]
(1)	1a	C6H5–	1.5	2a	82^a; 45^b	111; (110) [59]
(2)	1a	4-Cl–C6H4–	1.5	2b	88^a; 49^b	169-170; (168) [59]
(3)	1a	4-MeO–C6H4–	1.0	2c	79^a; 43^b	131; (132) [59]
(4)	1a	4-Br–C6H4–	1.0	2d	86^a; 55^b	175; (174) [59]
(5)	1a	4-Me–C6H4–	1.0	2e	77^a; 51^b	117; (118) [59]
(6)	1a		1.5	2f	74^a	115; (115) [59]
(7)	1a	E-C6H5CH=CH–	1.5	2g	87^a; 42^b	135-136; (136) [59]
(8)	1b	C6H5–	1.0	2h	84^a	132; (133) [59]
(9)	1b	4-Cl–C6H4–	1.5	2i	89^a	143-144; (144) [59]
(10)	1b	4-Me–C6H4–	1.5	2j	76^a	120; (120) [59]
(11)	1b	4-Me2N–C6H4–	1.0	2k	81^a	140; (140) [59]
(12)	1b		1.5	2l	73^a	134-135; (135) [59]
(13)	1b	2-Furanyl	1.5	2m	80^a	101; (101) [42]
(14)	1b	4-MeO–C6H4–	1.5	2n	72^a	104
(15)	1b	E-C6H5CH=CH–	1.5	2o	85^a	148; (148) [59]
(16)	1c	C6H5–	1.5	2p	74^a	120; (120-121) [60]
(17)	1c	4-Cl–C6H4–	1.5	2q	84^a; 51^b	133-134; (132-133) [60]
(18)	1c	4-MeO–C6H4–	1.5	2r	75^a; 46^b	88; (87-88) [60]
(19)	1c	4-Br–C6H4–	1.5	2s	82^a	158
(20)	1c	E-C6H5CH=CH–	1.5	2t	82^a; 48^b	134; (133-134) [61]
(21)	1d	4-Me–C6H4–	1.5	2u	76^a	139-140; (137-138) [62]
(22)	1d	4-MeO–C6H4–	1.5	2v	71^a	139-140; (138-139) [62]
(23)	1d	4-Br–C6H4–	1.5	2w	83^a; 53^b	188-189
(24)	1d	E-C6H5CH=CH–	1.5	2x	88^a; 45^b	125; (124-125) [61]

^aOver anhy. K₂CO₃; ^bover neutral alumina.