摘要:

AbstractSynthetic approaches to cyclic phosphonium ylides are reviewed and the syntheses are classified according to reaction type rather than ring size. Particular attention is paid to syntheses leading to isolable or easily characterizable cyclic ylides and a number of other reactions in which cyclic phosphonium ylides are postulated as transient intermediates are discussed. There is also a brief discussion regarding structure and bonding in certain of the more stable cyclic ylides such as the 1,1‐disubslituted phosphorins and certain diphosph(V)orin

ISSN:0022-152X    

DOI:10.1002/jhet.5570090101

出版商:Wiley‐Blackwell    

年代:1972

数据来源: WILEY

摘要:

AbstractMalonimidoacetic acid derivatives (VIII, XIII) were synthesized as a potential penicillin analogs, hut they failed to inhibit the growth of bacteria when testedin vitroagainst a range of Gram‐positive and Gram‐negative microorgani

ISSN:0022-152X    

DOI:10.1002/jhet.5570090102

出版商:Wiley‐Blackwell    

年代:1972

数据来源: WILEY

摘要:

AbstractAn analysis of the ir and nmr spectra taken on a series of nine different alkyl 2‐picolyl ketones clearly indicates that there is an enol‐keto tautomerism. The enol:keto ratio exhibits a marked dependence on both solvent polarity and the nature of the alkyl group. The equilibrium values correlate with the Taft sleric substituent consta

ISSN:0022-152X    

DOI:10.1002/jhet.5570090103

出版商:Wiley‐Blackwell    

年代:1972

数据来源: WILEY

摘要:

AbstractThe synthesis of a series of heterocyclic derivatives of 3,5‐dinitro‐o‐toluic acid is desc

ISSN:0022-152X    

DOI:10.1002/jhet.5570090104

出版商:Wiley‐Blackwell    

年代:1972

数据来源: WILEY

摘要:

AbstractThe crystal and molecular structure of 1,1,4,4‐tetraphenyl‐1,4‐diphosphoniacyclohexane dibromide has been determined by a single‐crystal, x‐ray diffraction study using diffractometer data. The compound crystallizes in the monoclinic space group P21/c with unit cell constants of a = 12.777(1), b = 26.180 (2), c = 16.283 (1) Å, and β = 91.18(1)°. The structure was solved by the heavy atom method with the 4176 independent and statistically significant structure factors refining to a value of R = 0.07. The diphosphonium ring is in the chair conformation with each phosphorus ion having an axial and equatorial phenyl ring attached. P‐C and C‐C bond lengths of 1.78 ± .03 Å and 1.53 ± .03 Å respectively agree well with the literature value

ISSN:0022-152X    

DOI:10.1002/jhet.5570090105

出版商:Wiley‐Blackwell    

年代:1972

数据来源: WILEY

摘要:

AbstractThe chemistry of several of the Diels‐Alder adducts formed by the reaction of 4,4‐diethylpyrazoline‐3,5‐dione (1) with conjugated dienes was studied with respect to reduction (hydride and catalytic) and reaction with base. Reaction of the 2,3‐dimethyl‐1,3‐butadiene adduct with lithium aluminum hydride followed by hydrogenation gave 1,3,5,6,7,8‐hexahydro‐cis‐endo‐6,7‐dimethyl‐2,2‐diethylpyrazolo[1,2‐a]pyridazine (11). Attempted conversion of this compound to 3,3‐diethyl‐cis‐7,8‐dimethyl‐1,5‐diazacyclononane (12) gave instead a compound which has been tentatively identified asN‐(2,3‐dimethyl‐4‐aminobutyl)‐2‐ethyl‐2‐methylbutanaldimine (14). Lithium aluminum hydride reduction of 4,4‐diethylpyrazolidine‐3,5‐dione (22) or the adducts formed from1and cyclopentadiene or 1,3‐cyclohexadiene gave good yields of 4,4‐diethylpyrazolidine (21). This later reduction gave a new and efficient synthetic route to the pyrazolidine ring system. Lithium aluminum hydride reduction of 5,6,7,8‐tetrahydro‐5,8‐ethano‐2,2‐diethylpyrazolo[1,2‐a]pyridazine‐1,3(2H)dione (26) followed by hydrogenolysis led to a high yield of 4,4‐diethyl‐2,6‐diazabicyclo[5.2.2]undecane (28) which is the first reported example of this ring system. Reaction of several of the adduc

ISSN:0022-152X    

DOI:10.1002/jhet.5570090106

出版商:Wiley‐Blackwell    

年代:1972

数据来源: WILEY

摘要:

AbstractSyntheses of several 1‐spiroisoquinoline derivatives (VIII, IX, X, XI, XII, XIII, and XIV) were carried out and their unique mass spectral fragmentations were reported. The presence of carbonyl groups at the C‐9 and C‐14 positions caused cleavage of the five membered ring through the elimination of one or two carbon monoxide groups. This led to the formation of the three membered ring system on the fragmentation pa

ISSN:0022-152X    

DOI:10.1002/jhet.5570090107

出版商:Wiley‐Blackwell    

年代:1972

数据来源: WILEY

摘要:

AbstractThe effect of 4‐substituents on the stability of pyridinium dicarbethoxymethylides, as determined by pKameasurements, is found to correlate well with their effect on the stability of similarly substituted pyridine 1‐oxides. Displacements in chemical shift in the ylides, particularly of the α‐protons, are also found to correlate well with substituent effects. Intramolecular charge‐transfer transitions in the electronic spectra, characteristic of pyridinium ylides, are

ISSN:0022-152X    

DOI:10.1002/jhet.5570090108

出版商:Wiley‐Blackwell    

年代:1972

数据来源: WILEY

摘要:

AbstractThe mass spectra of six furfuryl compounds — namely, furfuryl alcohol, 5‐furfuryl‐furfuryl alcohol, difurfuryl ether, difurylmethane, 2,5‐difurfurylfuran, and 4‐furfuryl‐2‐pentenoic acid‐γ‐lactone — have been studied. Their fragmentation mechanisms are discussed in detail with particular emphasis on the modes that lead to the formation of aromatic fragments. The majority of the fragment ions are formed by elimination of CO and C2H2from even‐electron precursor ions and HCO from odd‐electron precursor ions. Molecules containing two furan rings linked by a methylene group give mass spectra that exhibit large abundances o

ISSN:0022-152X    

DOI:10.1002/jhet.5570090109

出版商:Wiley‐Blackwell    

年代:1972

数据来源: WILEY

摘要:

AbstractCleavage of the aryl‐silicon bond of 2‐trimethylsilyl‐1‐methylimidazole (Ia) and 2‐trimethylsilyl‐1‐methylbenzimidazole (Ib) has been effected by five carbonyl reagents, i.e. aldehydes, acid halides, chloroformates, anhydrides and isocyanates, to provide a novel synthetic route to a host of functionally substituted heterocycles. Compound Ia reacted exothermically at room temperature, with four of the, five carb

ISSN:0022-152X    

DOI:10.1002/jhet.5570090110

出版商:Wiley‐Blackwell    

年代:1972

数据来源: WILEY