Entry

R¹

R²

X

Yields^b (%)

Mp (℃)^c

Found

Reported (lit.)

4a

C₆H₅

EtO

O

96

201-202

200-202 [20]

4b

4-Me-C₆H₄

EtO

O

97

209-211

209-212 [21]

4c

3-MeO-C₆H₄

EtO

O

93

219-221

219-220 [20]

4d

4-F-C₆H₄

EtO

O

98

175-176

175-177 [22]

4e

2-Cl-C₆H₄

EtO

O

93

211-213

211-213 [23]

4f

2-Br-C₆H₄

EtO

O

93

202-204

205-207 [24]

4g

2-Cl-4-F-C₆H₃

EtO

O

88

195-197

4h

2-Cl-5-F-C₆H₃

EtO

O

82

219-221

4i

3-Br-4-F-C₆H₃

EtO

O

85

193-195

4j

3,4-(HO)₂-C₆H₃

EtO

O

89

232-234

233-235 [20]

4k

C₆H₅

EtO

S

83

201-204

202-204 [25]

4l

4-Me-C₆H₄

EtO

S

90

184-186

185-186 [26]

4m

3-MeO-C₆H₄

i-PrO

O

94

196-198

4n

4-HO-C₆H₄

i-PrO

O

98

192-194

4o

4-N(CH₃)₂-C₆H₄

i-PrO

O

89

260-263

4p

4-F-C₆H₄

t-BuO

O

99

147-149

4q

3-Me-C₆H₄

t-BuO

O

93

217-219

4r

3-MeO-C₆H₄

t-BuO

O

95

212-214