2-Nitrobenzyl ethers

Chlorophenyl 2-nitrobenzyl ether [109669-56-9] M 263.7, m 69 . Crystd from EtOH. 

Scheme 3.—Proposed Mechanism for the Photochemical Cleavage of 2-Nitrobenzyl Ethers and 2-Nitrobenzyl Glycosides.

Chlorophenyl isothiocyanate [2131-55-7] M 169.6, m 44 , 43-45 , 45 , 46 , 47 , b 110-115 /4mm, 135-136 /24mm. Check the IR first. Slur with pet ether (b 30-60°) and decant the solvent. Repeat 5 times. The combined extracts are evap under reduced press to give almost pure compound as a readily crystallisable oil with a pleasant anise odour. It can be recrystd from the minimum vol of EtOH at 50° (do not boil too long in case it reacts). It can be purified by vac distn. Irritant [Org Synth Coll Vol V 223 7975]. 4-Chlorophenyl 2-nitrobenzyl ether, M 263.7, m 69 ,... 

In composite plastic microchannels, there is an additional problem of extra dispersion (Taylor dispersion) in EOF which is caused by the difference in zeta potentials of the different materials forming the channels [258]. Caged fluorescent dye (fluorescein bis[5-carboxymethyoxy-2-nitrobenzyl]ether dipotassium salt) was used to visualize the greater dispersion obtained in acrylic or composite channels due to non-uniformity in the surface charge density [259]. 

Our second example again represents the photodeprotection of a 2-nitrobenzyl ether to liberate a phenol in a complex advanced intermediate en route to the putative structure of Diazonamide [Scheme 4.158].298... 

Problem 5.9. The 2-nitrobenzyl group is used as a base- and acid-stable but photolabile protecting group for alcohols. Draw a Norrish mechanism for the release of an alcohol from a 2-nitrobenzyl ether upon photolysis. 

Hellrung, B., Kamdzhilov, Y., Schworer, M., Wirz, J., Photorelease of Alcohols from 2 Nitrobenzyl Ethers Proceeds via Hemiacetals and May Be Further Retarded by Buffers Intercepting the Primary aci Nitro Intermediates, J. Am. Chem. Soc. 2005, 127, 8934 8935. 

Shimizu et al report that while [2.2] paracyclophane (55) undergoes two-photon dissociation in low temperature matrices by way of the triplet state, in the gas phase, the efficient two-photon process proceeds via a hot molecule formed by internal conversion from the initially formed singlet excited state. The photocleavage of 2-nitrobenzyl ethers and ester has been widely reported and has now been evaluated as a deprotection methodology for indoles, benzimidazole, and 6-chlorouracil (Voelker et al). The mechanism of the cleavage of such compounds is considered to involve the o-quinonoid intermediate, but previously these had only been deduced from transient electronic spectra produced in flash photolysis experiments. Infrared spectral data from photochemical studies of 2-nitrobenzyl methyl ether in argon and nitrogen matrices have now been published which confirm that the intermediate does indeed have the o-quinonoid structure... 

Fig. 13. The distribution of the symplasmic tracer (CMNB - caged fluorescein (fluorescein bis-(5-carboxymethoxy-2-nitrobenzyl ether, dipotassium salt) within the Ambidopsis somatic embryo, showing a border in symplasmic communication between the root meristem and other parts of the somatic embryo, which indicates that the symplasmic subdomains correspond with the main morphological parts of the embryo (fluorescence microscope h - hypocotyl, c - cotyledon, r - root bar = 150 pm author - Wrobel, PhD thesis).

Telfer and coworkers showed that the same nitrobenzyl groups could be incorporated into bpdc linkers and that the resultant zinc MOF [Zn40(bpdc-0CH2CgH4N02-2)3] has an IRMOF structure. Photolysis of powdered samples of this 2-nitrobenzyl ether with... 

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