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A thorough understanding of mechanisms of prey consumption by carnivores and the constraints on predation help us in evaluating the role of carnivores in an ecosystem. This is crucial in developing appropriate management strategies for their conservation and mitigating human-carnivore conflict. Current models on optimal foraging suggest that mammalian carnivores would profit most from killing the largest prey that they can subdue with minimal risk of injury to themselves. Wild carnivore diets are primarily estimated through analysis of their scats. Using extensive feeding experiments (n = 68) on a wide size range (4·5-130 kg) of obligate carnivores - lion, leopard, jungle cat and domestic cat, we parameterize biomass models that best relate consumption to scat production. We evaluate additional constraints of gut fill, prey digestibility and carcass utilization on carnivory that were hereto not considered in optimal foraging studies. Our results show that patterns of consumption to scat production against prey size are similar and asymptotic, contrary to established linear models, across these carnivores after accounting for the effect of carnivore size. This asymptotic, allometric relationship allowed us to develop a generalized model: biomass consumed per collectable scat/predator weight = 0·033-0·025exp(-4·284(prey weight/predator weight)) , which is applicable to all obligate carnivores to compute prey biomass consumed from scats. Our results also depict a relationship for prey digestibility which saturates at about 90% for prey larger than predator size. Carcass utilization declines exponentially with prey size. These mechanisms result in digestible biomass saturating at prey weights approximately equal to predator weight. Published literature on consumption by tropical carnivores that has relied on linear biomass models is substantially biased. We demonstrate the nature of these biases by correcting diets of tiger, lion and leopard in recent publications. Our analysis suggests that consumption of medium-sized prey was significantly underestimated, while large prey consumption was grossly overestimated in large carnivore diets to date. We highlight that additional constraints of prey digestibility and utilization combined with escalating handling time and risks of killing large prey make prey larger than the predator size unprofitable for obligate carnivores.

A Cu based shape memory alloy (Cu-Al-Ni) having a composition 83% Cu, 14% Al, 3% Ni, was developed and studied to determine the shape memory effect. Powder of Cu, Al and Ni was melted in a pit furnace at about 15500C, and casted alloy was heat treated at 8500C for a period of 50 minutes followed by water quenching. Microstructure characterization of alloy (Cu-Al-Ni) was carried out to determine the pre-quenched (cast structure) and quenched martensitic structure. The microstructure analysis of developed samples showed needle like structure of quenched martensite after heat treatment. It has a very good resemblance with structure of casted shape memory alloy obtained from the vacuum induction process. The Vickers hardness test was also performed. Quenched microstructure with improved hardness than pre-quenched structure was observed.Keywords: Shape Memory Alloy, Microstructure, Mechanical Properties

Recent developments1–3 in the synthesis of 4(1H)-pyridone derivatives have prompted us to communicate a highly versatile synthesis of this class of heterocycles. Acylation of the styrylamine (I)4 (R1 = C2H5) with a substituted arylacetyl halide (II) in ether at O[ddot]-30[ddot]C in the presence of triethylamine or pyridine gave in 2 to 24 hours the enaminoketone (III) (75%-85% trans-isomer together with 25%-15% cis-isomer based on chemical shift of CH methine proton). Enaminoketone (III) could be readily converted to (IIIa) with aqueous methylamine in ethanol or to the bis-enaminoketone (IV) with N,N-dimethylformamide dimethyl acetal. The enaminoketone (IIIa) could be cyclized to pyridone (V) by refluxing with N,N-dimethylformamide dimethyl acetal; alternatively, the bis-enaminoketone (IV) could be cyclized to pyridone (V) by overnight reflux with methylamine hydrochloride in ethanol. yields based on styrylamine were 30%-65%. These transformations are outlined in Scheme 1. As an example, the synt...

Uber die Struktur der roten Acylierungsprodukte von Pyridazinylhydrazonen Bei der Acylierung von Pyridazinylhydrazonen (3) mit Saurechloriden oder Anhydriden in Benzol entstehen scharlachrote Triazolo[4,3-b]pyridazine (4), deren Struktur durch Rontgenstrahlbeugungsanalyse gesichert wird.

The preceding communication reports on the synthesis of 3,5-diaryl-4(1H)-pyridone derivatives via enaminoketones derived from the acylation of styrylamines with substituted arylacetyl chlorides. In this paper we describe methods for the preparation of 4(1H)-pyridones bearing carboxylic acid, ester, nitrile, cycloalkyl, cycloalkenyl, and derived functional groups in the 3-position.

Cyclodehydrohalogenation by terminal N 1 -C 4 bond formation affords N-aryl-4-benzoyl-2-azetindinones from 3-benzoyl-3-bromopropionanilides in an unequivocal annelation process.

Two synthetic procedures have been developed for the preparation of azeto[1,2-a]quinoxaline- 1,3-diones, a novel class of fused heterocyclic β-lactams possessing a bridgehead nitrogen atom. Both processes are general and afford the title compounds in good yield. The infrared, proton magnetic resonance, and mass spectroscopic properties of the title compounds are discussed.

ω- (N-aryl-chloracetamido) -acetophenones have been cyclized with triethylamine in warm benzene solution to the corresponding 1,4-oxazines. The reaction appears to be general for any N-aryl substituent, as long as an overall electron-withdrawing substituent is present para- or meta, in the aromatic nucleus of the acetophenone moiety. The predominant tautomeric form present is shown by IR spectrography to be the “keto” tautomer in every case. The structure of one morpholine is confirmed by mass spectral fragmentation analysis.

Cyclodehydrohalogenation-beta-Lactams-Morpholin-3-ones-H'-NMR Spectroscopy N-Aryl-N-chloroacetyl-2-chlorophenacylamines (2) give morpholinones 3, or beta-lactams 4, depending upon the N-aryl-substituent. N-Phenyl-N- (2,3-dibromo-3-phenylpropionyl) -4-nitrophenacylamine did not undergo base-catalysed cyclization but gave, instead, the α,β-unsaturated, open-chain amide 5. N-Aryl-N-chloroacetyl-aminomethyl-2-naphthylketones afford only beta-lactams. The first attempt at the synthesis of a 2-chloro-3-oxo-morpholine resulted in the isolation of the 2-hydroxyderivative. The H1-NMR spectra of some more 3-oxo-morpholines have been recorded.

The new route to the synthesis of 3-oxo-1,4-oxazines 1 has been extended. N-aryl-N-chloroacetyl-m-nitro-phenacyl amines afford either only oxazine, or beta-lactam or both depending on the nature of the N-aryl substituent. A set of rules indicates from which precursors beta-lactam, as against morpholine formation, may be expected.

Aus der starken Aktivierung des Methinwasserstoffs in den Halogenacetaminomalonaten und -phenylacetaten 4 durch eine N-[4-Nitro-phenyl]-Gruppe bei der Cyclisierung zu den β-Lactamen 5 sowie der Lage der CO-Bande der Amidgruppe in 5 und der Ringbestandigkeit wird auf Coplanaritat des N-Nitrophenylrings mit den drei Valenzen des Stickstoffs in den Amiden 4 und Lactamen 5 geschlossen. In den N-[2-Chlor-4-nitro-phenyl]-und N-[2-Nitrophenyl]-halogenacetaminoestern 4h und i ist der Arylring aus der Ebene des sp2-Stickstoffs herausgedreht, begleitet von einer deutlichen Abnahme der Methinwasserstoff-Aktivierung.

The formation of a 2-oxo-azetidine from N-phenyl-N-chloroacetyl-4-fluoro-phenacylamine, and 3-oxo-morpholines from corresponding 4-bromo-derivatives 2 indicates the possibility of the existence of dπ-acceptor resonance between the aromatic ring and the bromo-substituent. H-NMR studies of some morpholines reported earlier 3 indicate a planar heterocyclic structure with a rapidly inverting N₋aryl substituent. Where the rotation of the N-aryl group is strongly hindered 16, the C2 methylene protons show a geminai coupling of -14.5 Hz4. The 2-oxo-azetidine (4) shows an ABX coupling pattern for its ring protons. Preliminary work attempting to extend the synthesis of morpholines to azepines has resulted instead in the formation of a pyrrolidone.

Two new derivatives of the 1,4-oxazine ring system (3a and 3b) derived from p-aminobenz-amides have been synthesized. The uv absorption spectra of sixteen representative 1,4-oxazines all show two high intensity bands (ϵ ∼ 105) between 220-400 ran. The positions and intensities of the absorption maxima have been correlated with the steric and electronic effects of the oxazine ring substituents.

The preparation and antimicrobial activity of a series of beta-lactams (3a-f) are described. These compounds were prepared from the 2+2 cycloaddition of beta,beta-disubstituted enamines with aryl isocyanates; compounds 3a-f underwent facile beta-lactam ring fission between aminal carbon atom C4 and the lactam nitrogen N1. The resisting formylacetanilide derivatives were devoid of antibiotic activity.

Potassium tertiary butoxide in dimethyl sulfoxide solution has been shown to act as an efficient base in effecting the cyclo-dehydrohalogenation of halogen-acylamino-esters and -ketones. For certain specific cyclizations it is superior to the bases thus far used, yielding compounds of high purity in short reaction times. The first reported synthesis of a piperidinone by this route has been achieved.

The preparation and antimicrobial activity of a series of beta-lactams (3a-f) are described. These compounds were prepared from the 2+2 cycloaddition of beta,beta-disubstituted enamines with aryl isocyanates; compounds 3a-f underwent facile beta-lactam ring fission between aminal carbon atom C4 and the lactam nitrogen N1. The resisting formylacetanilide derivatives were devoid of antibiotic activity.

Uber die Struktur der roten Acylierungsprodukte von Pyridazinylhydrazonen Bei der Acylierung von Pyridazinylhydrazonen (3) mit Saurechloriden oder Anhydriden in Benzol entstehen scharlachrote Triazolo[4,3-b]pyridazine (4), deren Struktur durch Rontgenstrahlbeugungsanalyse gesichert wird.

Since the discovery 11 of the activating effect of the N- (p-Nitro-phenyl)-group on the methine hydrogen of halogenacetamino esters, it has been found that the p-Acetyl-phenyl and m-Nitro-phenyl groups exert a similar effect. It has been shown that the delocalisation of the N-non-bonded electrons across the orbitals of the N-Aryl substituent is the governing factor in the cyclisation of the above systems, and the effect of the bulk of the N-Aryl substituent is relegated to a minor position.

Die Behandlung der Amide (II) mit K-tert.-butylat oder athanolischer KOH fuhrt zu unterschiedlicher Cyclisierung: Aus (IIa) bzw. (IIb) werden die Morpholin-Derivate (Ia) [hierbei wird gleichzeitig der C1-Substituent (R5) zur OH- Gruppe (R3) verseift] bzw. (Ib), aus (IIc) bzw. (IId) werden dagegen die Lactame (IIIa) bzw. (IIIb) erhalten.

The association of various structural and dynamic phenomena through the postulate of d pi resonance has potential additional predictive value.