Compounds No

R

Molecular formula

Melting point (˚C)

Color

Yield (%)

6a

H

C₂₃H₁₈N₄S

252

White

76

6b

NO₂

C₂₃H₁₇N₅O₂S

260 - 266

Dark yellow

68

6c

CF₃

C₂₄H₁₇F₃N₄S

220

White

70

6d

Cl

C₂₃H₁₇ClN₄S

248

White

66

6e

CH₃

C₂₄H₂₀N₄S

250

White

78