Ring Contractions of 3-Azido-4H-quinolizin-4-ones and 3-Azido-4H-azino[1,2 - x]pyrimidin-4-ones: a Novel Approach to 3-Aminoindolizines and their Aza Analogues

2008 ◽  
Vol 61 (2) ◽  
pp. 107 ◽  
Author(s):  
Simon Rečnik ◽  
Anton Meden ◽  
Branko Stanovnik ◽  
Jurij Svete

Thermal transformations of 3-azido-4H-quinolizin-4-ones 4a,b and 3-azido-4H-azino[1,2–x]pyrimidin-4-ones 4c,d, available from the corresponding heteroarylamines 2a–d, were studied. The reaction products were mostly dependent on the solvent. Thus, heating of 3-azido-1-cyano-4H-quinolizin-4-one (4a) in toluene afforded 2-(pyridin-2-yl)fumaronitrile 5a, whereas 3-amino-1-cyano-4H-quinolizin-4-one (8) was obtained on treatment of 4a in a mixture of toluene and trifluoroacetic anhydride. However, heating of 4a in acetic anhydride and in acetic acid resulted in a ring contraction to produce 3-(diacetylamino)indolizine-1-carbonitrile 6a and 3-(acetylamino)indolizine-1-carbonitrile 7a, respectively. Similarly, ring contractions took place on heating ethyl 3-azido-4-oxo-4H-quinolizin-1-carboxylate 4b and 3-azido-4H-azino[1,2–x]pyrimidin-4-ones 4c,d in acetic anhydride or acetic acid to produce the N-acetylated 3-aminoindolizine derivatives 6b, 7b and 3-aminoimidazo[1,2–x]azine derivatives 6c,d in 30–89% yields. The structures of compounds 5–8 were determined by NMR spectroscopy and X-ray diffraction.

1991 ◽  
Vol 56 (12) ◽  
pp. 2917-2935 ◽  
Author(s):  
Eva Klinotová ◽  
Václav Křeček ◽  
Jiří Klinot ◽  
Miloš Buděšínský ◽  
Jaroslav Podlaha ◽  
...  

3β-Acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) reacts with acetic anhydride in pyridine under very mild conditions affording β-lactone IVa and γ-lactones Va and VIIa as condensation products. On reaction with pyridine, lactones Va and VIIa undergo elimination of acetic acid to give unsaturated lactones VIIIa and IXa, respectively. Similarly, the condensation of 20β,28-epoxy-21,22-dioxo-18α,19βH-ursan-3β-yl acetate (IIIb) with acetic anhydride leads to β-lactone IVb and γ-lactone Vb; the latter on heating with pyridine affords unsaturated lactone VIIIb and 21-methylene-22-ketone Xb. The structure of the obtained compounds was derived using spectral methods, particularly 1H and 13C NMR spectroscopy; structure of lactone IVa was confirmed by X-ray diffraction.


1999 ◽  
Vol 23 (3) ◽  
pp. 178-179
Author(s):  
Wendy I. Cross ◽  
Kevin R. Flower ◽  
Robin G. Pritchard

The acetic acid esters of 1-(4-methylphenylazo)naphthalen-2-ol 1 and 2-(4-methylphenylazo)-4-methylphenol 3 are prepared and characterised by single crystal X-ray diffraction studies and 13C{1H}NMR spectroscopy; the position of the C(2)13C resonance for the ester is used to predict the position of resonant frequency of the equivalent carbon in the parent alcohols and hence, calculate the position of the azo-hydrazone equilibrium in these compounds.


1986 ◽  
Vol 41 (5) ◽  
pp. 581-586 ◽  
Author(s):  
Konrad Holl ◽  
Ulf Thewalt

Among the reaction products of S4N4 with SnCl4 in chloroform, that contains acetic acid and small amounts of water, there are two salts S4N4H+[SnCl5(H2O)]- (A) and (S3N2NH2+)2[SnCl6]2- (B), both containing protonated SnNm units. The crystal and molecular structures of A and B have been determined by X-ray diffraction. A: monoclinic, P21/c, a = 9.084(2), b - 23.758(4), c = 6.587(1) Å , β = 101.86(3)°, Dc = 2.383 g·cm-3 and Z = 4. B: monoclinic, P21/n, a = 9.882(3), b = 12.873(4), c = 6.807(2) Å , β = 93.77(5)°, Dc = 2.352 g·cm-3 and Z = 2. The structures of the cations in both compounds agree well with those found of other salts containing these cations.


Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7531
Author(s):  
Hui Dou ◽  
Yuxuan Zheng ◽  
Manyi Qu ◽  
Peng Chen ◽  
Chunlin He ◽  
...  

The nitration of chitin monomer in a mixture of nitric acid and acetic anhydride was conducted and a highly nitrated (3R,4R,6R)-3-acetamido-6-((nitrooxy)methyl)tetrahydro-2H-pyran-2,4,5-triyl trinitrate (1) was obtained. Its structure was fully characterized using infrared spectroscopy, NMR spectroscopy, elemental analysis, and X-ray diffraction. Compound 1 possesses good density (ρ: 1.721 g·cm−3) and has comparable detonation performance (Vd: 7717 m·s−1; P: 25.6 GPa) to that of nitrocellulose (NC: Vd: 7456 m·s−1; P: 23 GPa; Isp = 239 s) and microcrystalline nitrocellulose (MCNC; Vd: 7683 m·s−1; P: 25 GPa; Isp = 250 s). However, Compound 1 has much lower impact sensitivity (IS: 15 J) than the regular nitrocellulose (NC; IS: 3.2 J) and MCNC (IS: 2.8 J). Compound 1 was calculated to exhibit a good specific impulse (Isp: 240 s), which is comparable with NC (Isp: 239 s) and MCNC (Isp: 250 s). By replacing the nitrocellulose with Compound 1 in typical propellants JA2, M30, and M9, the specific impulse was improved by up to 4 s. These promising properties indicate that Compound 1 has a significant potential as an energetic component in solid propellants.


Molecules ◽  
2019 ◽  
Vol 24 (12) ◽  
pp. 2314 ◽  
Author(s):  
Luca Leoni ◽  
Andrea Carletta ◽  
Luca Fusaro ◽  
Jean Dubois ◽  
Nikolay A. Tumanov ◽  
...  

A number of salophen ligands and their Zn, Ni, and Pd complexes were synthesized by an efficient one-pot mechanosynthesis protocol. The reaction products were characterized by means of complementary solid-state techniques, i.e., powder X-ray diffraction, single-crystal X-ray diffraction, and solid-state NMR spectroscopy. Four new crystal structures of metal salophen complexes as DMSO solvates are here reported. The described simple and relatively fast (about 1 h for all derivatives) procedure is a good alternative to classical methods performed in organic solvents.


1997 ◽  
Vol 62 (5) ◽  
pp. 746-751 ◽  
Author(s):  
Andreas Franken ◽  
Jaromír Plešek ◽  
Christiane Nachtigal

On treatment of the [(1,2-C2B9H11)2Co]- ion with naphthalene in presence of AlCl3 a remarkably bridged [8,8'-μ-(CH2-C9H6)-(1,2-C2B9H10)2-3-Co]- ion is obtained as a single isolated compound. The triatomic -CH2-C9H6- bridge is derived from the rearranged naphthalene nucleus. The mechanism of this reaction is obscure but it does resemble the "Electrophile-Induced Nucleophilic Substitution" reported earlier. The structure of the compound was established by multinuclear NMR spectroscopy and by single crystal X-ray diffraction.


1993 ◽  
Vol 58 (12) ◽  
pp. 2924-2935 ◽  
Author(s):  
Jane H. Jones ◽  
Bohumil Štíbr ◽  
John D. Kennedy ◽  
Mark Thornton-Pett

Thermolysis of [8,8-(PMe2Ph)2-nido-8,7-PtCB9H11] in boiling toluene solution results in an elimination of the platinum centre and cluster closure to give the ten-vertex closo species [6-(PMe2Ph)-closo-1-CB9H9] in 85% yield as a colourles air stable solid. The product is characterized by NMR spectroscopy and single-crystal X-ray diffraction analysis. Crystals (from hexane-dichloromethane) are monoclinic, space group P21/c, with a = 903.20(9), b = 1 481.86(11), c = 2 320.0(2) pm, β = 97.860(7)° and Z = 8, and the structure has been refined to R(Rw) = 0.045(0.051) for 3 281 observed reflections with Fo > 2.0σ(Fo). The clean high-yield elimination of a metal centre from a polyhedral metallaborane or metallaheteroborane species is very rare.


2003 ◽  
Vol 42 (7) ◽  
pp. 2342-2349 ◽  
Author(s):  
Éva Csajbók ◽  
Zsolt Baranyai ◽  
István Bányai ◽  
Ernő Brücher ◽  
Róbert Király ◽  
...  

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