Effects of salinity and alkalinity on growth and survival of all-male giant freshwater prawn (Macrobrachium rosenbergii De Man, 1879) juveniles

All-male giant freshwater prawns (AMGFPs) have been a popular crop cultivated in the Mekong Delta, Vietnam, due to their proven production efficiency compared to all-female or mixed-sex prawn cultures. However, the crucial water quality factors impacting AMGFP aquaculture efficiency have yet to be elaborately investigated. Two separate experiments were randomly arranged with three replicates to evaluate the effects of salinity or alkalinity on the growth and survival of AMGFP juveniles during the grow-out period. The results show that the prawn survival rate in the salinity range of 0–15‰ varied from 66.1 to 74.8％ and in a salinity range of 0–5‰ was relatively low compared to the range of 10-15‰; however, the difference was not significant among salinities after 90 days of culture (p > 0.05). All the prawn growth performance parameters significantly decreased with increasing salinities of 0, 5, 10, and 15‰ after 30, 60, and 90 days of culture (p 0.05), and both were significantly higher than those at salinities of 10 and 15‰ (p < 0.05) after 90 days of culture. In addition, the survival rate reached 82.5–84.4％ and did not significantly differ among alkalinities of 80, 100, 120, 140, and 160 mgCaCO3 L−1. However, the growth performance parameters and yield of AMGFPs at an alkalinity of 160 mg L−1 were significantly higher than those at lower alkalinities (80, 100, 120, and 140 mg CaCO3 L−1) after 90 days of culture. Therefore, it is recommended that a salinity range of 0–5‰ and alkalinity of 160 mgCaCO3 L−1 is optimal for the growth-out culture of AMGFP juveniles

Domino synthesis of the first representative of a dibenzo(perhydropyrimidino)aza-14-crown-4-ethers series

[No abstract available

Domino synthesis of the first representative of a dibenzo(perhydropyrimidino)aza-14-crown-4-ethers series

[No abstract available

24-Acetyl-8,11,14-trioxa-24,27-diazapentacyclo[19.5.1.122,26. 02,7.015,20]octacosa-2,4,6,15(20),16,18-hexaen-28-one

The title compound, C25H28N2O5, is a product of the Petrenko-Kritchenko condensation of N-acetyl-piperidone with 1,5-bis(2-formylphenoxy)-3-oxapentane and ammonium acetate. The molecule comprises a fused pentacyclic system containing an aza-14-crown-3-ether macrocycle, two piperidone and two benzene rings. The aza-14-crown-3-ether ring adopts a bowl conformation. The dihedral angle between the benzene rings fused to the aza-14-crown-4-ether unit is 70.18 (4)°. The central piperidone ring has a boat conformation, whereas the terminal piperidone ring adopts a chair conformation. The conformation of the central piperidone ring is determined by two intramolecular N - H⋯O hydrogen bonds. In the crystal, molecules are linked by weak C - H⋯O interactions into chains along [010]. © 2012 International Union of Crystallography

Meso-(1S*,21R*)-25-methyl-8,11,14-trioxa- 22,24,25-triazatetracyclo-[19.3.1.02,7.015,20]pentacosa-2, 4,6,15(20),16,18-hexaene-23-thione chloroform monosolvate

The title compound crystallizes as a chloroform solvate, C 20H23N3O3S·CHCl3, with two crystallographically independent units. The independent units have distinctly different interaction patterns between the azacrown macrocycle and the chloroform solvent molecule. In one of them, the chloroform molecule forms C - H···N and Cl···H - C hydrogen bonds with the azacrown macrocycle (as a proton donor and an acceptor, respectively), whereas in the other, one of the chloroform molecules is bound to the azacrown macrocycle by an attractive Cl···O [3.080 (3)Å] interaction. The azacrown macrocycles of different units are structurally similar; the aza-14-crown-3-ether ring adopts a bowl conformation with dihedral angles between the planes of the fused benzene rings of 60.7 (1) and 68.0 (1)°. The triazinanethione ring in both cases has a sofa conformation. The crystal packing is characterized by N - H···S, N - H···O, C - H···Cl and C - H···S hydrogen bonds

Crystal structure of (1RS,21SR,22RS,24SR)-28-oxo-24-propyl-8,11,14-trioxa-24,27-diazapentacyclo[19.5.1.122,26.02,7.015,20]octacosa-2,4,6,15(20),16,18-hexaene acetic acid monosolvate

The title compound, C26H32N2O4(M)·C2H4O2, (I), is the product of the Petrenko-Kritchenko condensation of N-propylpiperidinone with 1,5-bis(2-formylphenoxy)-3-oxapentane and ammonium acetate. In M, the aza-14-crown-3-ether ring adopts a bowl conformation, with the configuration of the C - O - C - C - O - C - C - O - C polyether chain being t-g (-)-t-t-g (+)-t (t = trans, 180°; g = gauche, ±60°). The dihedral angle between the planes of the benzene rings fused to the aza-14-crown-4-ether moiety is 62.75 (5)°. The central piperidinone ring has a boat conformation, whereas the terminal piperidinone ring adopts a chair conformation. The boat conformation of the central piperidinone ring is supported by the bifurcated intramolecular N - H⋯O hydrogen bond. In the crystal, each solvent molecule is linked to molecule M via strong O - H⋯N hydrogen bonding, forming hydrogen-bonded pairs of molecules, which further interact through weak C - H⋯O hydrogen bonds, forming layers parallel to the ac plane. © 2016

Dimethyl 2-[24-acetyl-28-oxo-8,11,14-trioxa-24,27-diaza-penta-cyclo-[19.5. 1.122,26.02,7.015,20]octa-cosa-2,4,6,15(20),16, 18-hexaen-27-yl]but-2-enedioate

The title compound, C31H34N2O9, is a product of the Michael addition of the cyclic secondary amine subunit of the (bis-pidino)aza-14-crown-4 ether to dimethyl acetyl-ene-dicarboxyl-ate. The mol-ecule comprises a tricyclic system containing the aza-14-crown-3 ether macrocycle and two six-membered piperidinone rings. The aza-14-crown-3-ether ring adopts a bowl conformation with a dihedral angle between the planes of the fused benzene rings of 51.14 (5)°. The central piperidone ring has a boat conformation, whereas the terminal piperidone ring adopts a chair conformation. The dimethyl ethyl-enedicarboxyl-ate fragment has a cis configuration with a dihedral angle of 56.56 (7)°between the two carboxyl-ate groups. The crystal packing is stabilized by weak C-H⋯O hydrogen bonds

Ethyl 23-benzyl-8,11,14-trioxa-23,28,29-triazapentacyclo[19.7.1.0 2,7.015,20.022,27]nonacosa-2,4,6,15(20),16,18, 21,26-octaene-26-carboxylate

The title compound, C33H35N3O5, is the product of the multicomponent condensation of 1-benzyl-4- ethoxycarbonylpiperidin-3-one with 1,5-bis(2-formylphenoxy)-3-oxapentane and ammonium acetate. The molecule comprises a pentacyclic system containing the aza-14-crown-4-ether macrocycle, tetrahydropyrimidine, tetrahydropyridine and two benzene rings. The aza-14-crown-4-ether ring adopts a bowl conformation with a dihedral angle of 62.37 (5)° between the benzene rings. The tetrahydropyrimidine ring has an envelope conformation with the chiral C atom as the flap, whereas the tetrahydropyridine ring adopts a distorted chair conformation. Two amino groups are involved in intramolecular N-H⋯O hydrogen bonds. In the crystal, weak C-H⋯O hydrogen bonds link the molecules into layers parallel to the ab plane

One-stage synthesis of 1,4-bis(8,11,14-trioxa-25-azatetracyclopentacos-23- yl)benzene

[No abstract available