tert-Butyl N-[N,N-bis(2-chloroethyl)sulfamoyl]-N-(2-chloroethyl)carbamate

The title compound, C11H21Cl3N2O4S, was produced as part of a development programme of a new synthetic route to chloroethylnitrososulfamides (CENS) with three chloroethyl moieties. These compounds possess structural features that confer potential biological activity and act as alkylating agents. The packing is governed by four weak C—H⋯O interactions, forming an infinite three-dimensional network.

The title compound, C 11 H 21 Cl 3 N 2 O 4 S, was produced as part of a development programme of a new synthetic route to chloroethylnitrososulfamides (CENS) with three chloroethyl moieties. These compounds possess structural features that confer potential biological activity and act as alkylating agents. The packing is governed by four weak C-HÁ Á ÁO interactions, forming an infinite three-dimensional network.
In order to extend our knowledge about such sulfamides derivatives with three N-(2-chloroethyl) moieties the crystal structure of the title compound is presented.
In all essential details, the molecular geometry in terms of bond distances and angles is in good agreement with related structure (Dokhane et al. 2002). In the molecular geometry ( Fig.1), the sulfamide moiety N1-S-N2 exhibit an asymmetry of S-N bond distance, with values of 1.688 (1) and 1.615 (1) Å respectively. The molecules are linked by four C-H···O intermolecular interactions involving sulfonamide (oxygen atoms O1 and O2) and carbonyl (oxygen atom O3) functions (table 1). Thus, these interactions lead to an infinite three-dimensional network.

Experimental
The synthetic pathway used for the preparation of the title compound is outlined in Fig. 2. First the formation of tert-butylN-(2-chloroethyl)sulfamoylcarbamate which is performed in dried dichloromethane with successive addition of tBuOH, and Chloroethylamine/TEA into CSI. After purification, the carbamate was recovered at (yield 80%). The second step is carried out according to the Mitsunobu procedure (Mitsunobu, 1981) in anhydrous THF as a solvent. The mixture of DEAD (diethyl azodicarboxylate) and tert-butylN-(2-chloroethyl)sulfamoylcarbamate is added to a solution of excess of chloroethanol and PPh3. The product was recrystallized in pure ethanol.

Refinement
H atoms bonded to C atoms were positioned geometrically and refined isotropically using a riding model (including free rotation about the ethanol C-C bond), with C-H = 0.97 Å (methylene) or 0.96Å (methyl) and with U iso (H) = 1.2 (1.5 for methyl groups) times U eq (C).