Syntheses and Biological Activity of Some Derivatives of C-9154 Antibiotic

Table 1

Synthesized C-9154 analogue and its derivatives.

Sample code	Type	Yield (mg)	Melting point (^°C)	Physical state
IA/01/1	C-9154 analogue	90%	195-196	White powdery solid
IA/24/1/B	Methyl ester	160, (0.78 mmol)	74	Bright yellow crystalline solid
IA/21/1/B	Ethyl ester	100, (0.46 mmol)	63	Light brown crystalline solid
IA/22/1/B	n-propyl ester	170, (0.73 mmol)	55	Dark brown crystalline solid
IA/23/1/B	Isopropyl ester	105, (0.45 mmol)	70	Dark brown crystalline solid
IA/19/1/B	n-butyl ester	200, (0.81 mmol)	42	Yellow waxy solid
IA/20/1/B	2-butyl ester	150, (0.61 mmol)	40	Golden brown oil
IA/25/1/B	t-butyl ester	2, (~0.01 mmol)	Not determined

The yield from the t-butyl derivative was too little and could not be optimized. This was probably due to steric hindrance from the methyl groups.