N-Nitroso-Vancomycin Impurity 26

(3S,6R,7R,22R,23S,26R,36R,38aR) -3- (2-amino-2-oxoethyl) -19,45-dichloro-7,22,28,30,32,44-hexahydroxy-6- ((R) -4-methyl-2- (methyl (nitroso) amino) pentanamido) -2,5,24,38,39-pentaoxo-2,3,4,5,6,7,23,24,25,26,36,37,38,38a-tetradecahydro-1H,22H-23,36- (epiminomethano) -8,11:18,21-dietheno-13,16:31,35-di (metheno) benzo[n][1]oxa[6,9]diazacyclohexadecino[4,5-d][1]oxa[7,17]diazacyclotetracosine-26-carboxylic acid