Results DNBZ (Ama 310 nm), DNBF (Amm 375 nm), and MDNBZ (Amm 375 nm) behave similarly in methanol and give rapidly the very stable yellow-colored adducts 3a, 3b, and 4 in the absence of any added methoxide: Am, 3a 465 nm; t 27 300 M-'cm-l; 460 nm; 6 29 170 Ml cm-'; Am: 450 nm; t 27 500 Ml cm-'. The three adducts have been characterized by their NMR~ pectra."~*'~ An X-ray study of 4 has also been rep~ rted.'~ Using the stopped-flow ...