Aliphatic nitro-compounds—LIII

Piotrowska, H.; Serafin, B.; Urbański, T.

doi:10.1016/s0040-4020(01)99184-7

Cited by 5 publications

(3 citation statements)

References 4 publications

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“…The "semi-planar" form 4, with an "axial" nitro group, has been suggested by Urbanski et al (2) for the phenylboronates of 2-alkyl-2-nitro-1,3-propanediols on the basis of calculated and experimentally determined dipole moments. It is noteworthy that these nitro derivatives were found to be more stable than other cyclic phenylboronates with respect to hydrolytic agents (3). This finding would also be consistent with intramolecular 0 + B coordination leading to a shielded sp3 boron center.…”

Section: Introductionsupporting

confidence: 57%

Structural studies of organoboron compounds. XXIV. 5-Methyl-5-nitro-2-phenyl-1,3-dioxa-2-boracyclohexane

Kliegel¹,

Preu²,

Rettig³

et al. 1986

Can. J. Chem.

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. Can. J. Chem. 64, 1855 (1986). The title compound was prepared according to the literature in order to determine whether it has a bicyclic cage structure resulting from intramolecular 0 --+ B coordination or a monocyclic boronate structure incorporating a trigonal planar boron atom. Crystals or 5-methyl-5-nitro-2-phenyl-l,3-dioxa-2-boracyclohexane are orthorhombic, a = 17.2358(4), b = 6.5007(2), c = 9.9225(3) A, Z = 4, space group Pnam. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.064 and R,. = 0.070 for 798 reflections with 1 r 3u(I). The nlolecule actually has Cl symmetry but, in the solid state, is located at a site of crystallographic C, symmetry. In order to maintain the apparent mirror symmetry the nitro oxygen atoms are disordered over two mirror-related rotational positions around the C(2)-N bond. The molecule was found to have a monocyclic boronate structure, in agreement with earlier predictions. Tile six-membered heterocyclic ring has a "semi-planar" conformation. Bond distances and angles are normal. [Traduit par la revue]

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Section: Introductionsupporting

confidence: 57%

Structural studies of organoboron compounds. XXIV. 5-Methyl-5-nitro-2-phenyl-1,3-dioxa-2-boracyclohexane

Kliegel¹,

Preu²,

Rettig³

et al. 1986

Can. J. Chem.

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“…To prepare an initiator based on methyl substituted nitroxide diol 4a, the hydroxy groups of 2-nitro-2-methyl-1,3propanediol (14) were protected as acetal 15 using benzaldehyde following the procedure of Piotrowska et al 17 Although our general procedure for nitrone formation usually involves a one-pot reaction involving reduction of the nitro compound to the hydroxylamine, followed by in situ condensation with an aldehyde, with this substrate, a two-step procedure gave superior results. Both benzaldehyde and isobutyroaldehyde were utilized to prepare ni-trones 16 and 18, respectively (Scheme 3).…”

Section: Figurementioning

confidence: 99%

“…After the product was concentrated in vacuo, the crude product was recrystallized with cold EtOH to give the product 15 (0.3337 g, 75%) as a white solid; mp 119-120 °C (recrystallized from EtOH, Lit. 17 Methyl-2-phenyl[1,3]dioxan-5-yl)-N-(2-methyl-1-phenylpropyl)…”

Section: -Methyl-5-nitro-2-phenyl-13-dioxane (15)mentioning

confidence: 99%

The Synthesis and Evaluation of New α-Hydrogen Nitroxides for ‘Living’ Free Radical Polymerization

Braslau¹,

O'Bryan²,

Nilsen³

et al. 2005

Synthesis

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Three N-alkoxyamines were synthesized for use in nitroxide-mediated radical polymerization. Upon thermolysis, they generate new acyclic a-hydrogen nitroxides: one adamantyl substituted and two diol-containing nitroxides. The initiators were tested in polymerization reactions in direct comparison with the initiator derived from the nitroxide TIPNO.Nitroxide-mediated 'living' free radical polymerization (NMRP) has become a very attractive method for the controlled polymerization of olefins, as monomers bearing a wide variety of functionality can be tolerated under the polymerization conditions. The resulting polymers generally display good control over both molecular weight and polydispersity, and the 'living' nitroxide endcap allows for the preparation of nanoscopic materials with highly designed architecture. 1 Other 'living' radical techniques such as Atom Transfer Radical Polymerization (ATRP) mediated by a metal complex, 2 and Reversible Addition Fragmentation Transfer (RAFT) mediated by a thiocarbonyl intermediate 3 have also been developed. ATRP has the advantage that it can be run at lower temperatures, and it functions well with methacrylates, but amine containing monomers sometimes coordinate to the metal catalyst, interfering with the polymerization process. Polymers made by ATRP contain traces of metal, derived from the metal catalyst. RAFT polymerization is effective with a wider range of monomers, including electron rich vinyl acetates, which are not good substrates for NMRP and ATRP. However sulfur-containing impurities may lead to undesirable colored polymers prepared by the RAFT process.Thus all three methods constitute valuable options in the methodologies available for producing designed polymers using free radical intermediates, yet there is room for improvement. With NMRP, an important achievement would be developing a system that would allow polymerizations to be carried out at temperatures lower than the 105-125 °C that are typically employed. The ability to polymerize electron rich olefins in a controlled manner would further extend the versatility of NMRP. For all of these goals, the characteristics of the nitroxide end-cap are key to improving the polymerization profile. Previously, we 4 and the group of Tordo 5 have introduced a-hydrogen nitroxides TIPNO 1 and SG-1 2, which are effective in the polymerization of styrenes and a variety of electron poor olefin monomers. Very recently a number of cyclic 6 and acyclic 7 new nitroxides have been introduced for improved efficacy in NMRP. Herein we present work on initiators based on several new acyclic a-hydrogen nitroxides for NMRP, in which the N-tert-butyl has been modified.

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