Adducts from 1,3,5-Trinitrobenzene

Adducts from 1,3,5-Trinitrobenzene 1. With alkoxides and hydroxide 

Solutions of 1,3,5-trinitrobenzene in methanol containing sodium methoxide are orange-coloured. The visible spectrum with maxima at 

Spectroscopic Data for 1 1 Adducts from Alkyl Picrates 

0 Downfield from tetramethylsilane 6 Gold and Rochester (1964a) Abe (1966) Crampton and Gold (1964a) Servis (1967) Foster and Mackie (1963) Foster and Fyfe (1965) Foster et al. (1965) Zollinger et al. (1967) Crampton (1967), Crampton (1965) Foster et al. (1967). 

4250 and 4950 A is very similar to that of the adducts of picryl ethers with alkoxide and this has suggested an analogous mode of interaction (Foster, 1959) with the formation of the adduct 13. This formula is supported by NMR measurements (Crampton and Gold, 1964a). In the 

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The spectral data for a variety of 1 1 and 1 2 adducts are collected in Table 2. As with the adducts from picryl ethers the visible spectra of 1 1 adducts from trinitrobenzene show two visible maxima whereas the 1 2 adducts have a single rather broad visible absorption. The NMR spectra of the 1 1 adducts show, typically, two bands due to ring protons, often exhibiting spin-spin coupling, at c. —8 4 (relative intensity 2) and — 6-0 p.p.m. (relative intensity 1). The position of the low-field band shows little dependence on the nature of the added group,... 

D. Adducts from Other Substituted Trinitrobenzenes 1. Picric acid... 

A kinetic smdy of the formation of zwitterionic adducts (28) from 1,3,5-trinitrobenzene and diazabicyclo derivatives indicates that reactions are surprisingly slow, with rate constants many orders of magnitude lower than those for related reactions with primary or secondary amines. The use of rapid-scan spectrophotometry was necessary to study the kinetics of reaction of 4-substimted-2,6-dinitro-A -n-butylanilines (29) with n-butylamine in DMSO the two processes observed were identified as rapid deprotonation to give the conjugate base and competitive a-adduct formation at the 3-position. The reactions of MAf-di-n-propyl-2,6-dinitro-4-trifluoromethylaniline (30), the herbicide trifluralin, and its A -ethyl-A -n-butyl analogue with deuteroxide ions and with sulfite ions in [ H6]DMS0-D20 have been investigated by H NMR spectroscopy. With deuteroxide a-adduct formation at the 3-position is followed by... 

The rates of adduct formation follow an inverted trend with respect to that found to the related stabilities. For example, the reaction of MeO with 3,5-dinitropyridine is slightly slower than that with 1,3,5-trinitrobenzene. The higher stability of the heterocyclic adduct 1 results in this case from a relatively low reverse rate. 

Two substrates of special interest are 2-(2-hydroxyethoxy)-3-nitro-thiophene and its 3-(2-hydroxyethoxy)-2-nitro isomer. Both compounds form Meisenheimer-type spiro adducts, 135 and 136, by ring closure at the 2-and 3-positions, respectively.177 Intramolecular cyclization brings in an extra driving force for the formation of the adduct, which is also observed in the trinitrobenzene series.31 This would account for the structure of adduct 136, which exceptionally bears the sp3-hybridized carbon on a ft position. No other examples of such a structure from 5-membered heteroaromatic substrates is known even for transient species, except for benzoannelated derivatives (see Section III,A,3). 

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