Table 3.

Microflow amide bond formation with various substrates.

Entry	Structure of	Cond.	Yield [%]
	desired product		(desired)	(epimer)
1		flow A[a] batch[d]	92 57	1 2
2		flow B[b] batch[d]	quant. 40	<1 <1
3		flow B[b] batch[d]	92 75	2 17
4		flow A[a] batch[d]	94 71	<1 1
5		flow C[c] batch[d]	97 74	3 18
6		flow B[b] batch[d]	89 47	<1 1
7		flow A[a] batch[d]	80 58	<1 1
8		flow A[a] batch[d]	74 53	<1 <1
9		flow A[a] batch[d]	98 <28	<1

^[a] Carboxylic acid: 2.5 equiv, triphosgene: 0.4 equiv.

^[b]Carboxylic acid: 3.0 equiv, triphosgene: 0.5 equiv.

^[c]Carboxylic acid: 2.5 equiv, triphosgene: 0.4 equiv, DIEA: 2.5 equiv, solvent A: MeCN, reaction temperature: 10 °C.

^[d]Reaction time for the activation of carboxylic acid and the amidation: 30 s. Fmoc=9-fluorenylmethyloxycarbonyl.