Chemicals & Distribution

Allessan CAP: The versatile and cost saving coupling reagent

Propylphosphonic acid anhydride (Allessan® CAP) is a non-toxic, non-allergenic, non-sensitizing coupling reagent for selective activation of carboxyl groups, besides other nucleophilic functional groups

Due to its outstanding properties, it is safe to handle and easy to store. Additionally, using Allessan® CAP will lower your overall process costs, compared to staying with the standard protocol, applying DCC/ HOBt.

Use of coupling reagents for converting carboxylic acids is nowadays widely spread. Specialized coupling reagents, enabling direct condensation of a carboxylic acid moiety and an alcohol or amine, offer a superior direct approach towards highly valuable carboxylic acid derivatives. Among these coupling reagents, Allessan® CAP offers a wide range of benefits.

Apart from its long shelf life (36 months), its high thermal stability (up to 300°C) and its excellent safety profile (no CMR-properties associated), Allessan® CAP proves to be the no. 1 alternative to coupling reagents such as DCC/HOBt, EDC, or CDI.

Being produced in Germany in an ISO9001 & ISO14001 certified facility for more than one decade, no supply chain interruptions due to tightened environmental regulations are to be expected, giving peace of mind to any procurement/supply chain associate.

Besides its outstanding properties, Allessan® CAP offers serious cost savings switching to an alternative protocol (figure 2). This is the case for example for the synthesis of active pharmaceutical ingredients (APIs) using Allessan® CAP (see figure 3).

Possible uses of Allessan® CAP include amidations, esterifications, Swern-type oxidations as substitute for oxalyl dichloride, and as catalyst during Aza-Diels-Adler reactions.

For more information please contact us via


WeylChem International GmbH

Alt Fechenheim 34
60386 Frankfurt

+49 69 506 820 2223