Different hydrogen-bonded chains in the crystal structures of three alkyl N-[(E )-1-(2-benzylidene-1-methylhydrazinyl)-3- hydroxy-1-oxopropan-2-yl]carbamates

Peer reviewedPublisher PD

Benzyl N-(2-hy­droxy-1-{N′-[(1E)-2-hy­droxy­benzyl­idene]hydrazinecarbon­yl}eth­yl)carbamate

The mol­ecule of the title compound, C18H19N3O5, adopts a curved arrangement with the terminal benzene rings lying to the same side. The hydroxyl­benzene ring is close to coplanar with the adjacent hydrazine residue [dihedral angle = 11.14 (12)°], an observation which correlates with the presence of an intra­molecular O—H⋯N hydrogen bond. The benzyl ring forms a dihedral angle of 50.84 (13)° with the adjacent carbamate group. A twist in the mol­ecule, at the chiral C atom, is reflected in the dihedral angle of 80.21 (12)° formed between the amide residues. In the crystal, two-dimensional arrays in the ac plane are mediated by O—H⋯O and N—H⋯O hydrogen bonds

Benzyl N-(1-{N′-[(E)-2-chloro­benzyl­idene]hydrazinecarbon­yl}-2-hy­droxy­eth­yl)carbamate

The mol­ecule of the title compound, C18H18ClN3O4, is twisted about the chiral C atom with the dihedral angle between the two amide residues being 87.8 (5)°, but, overall, it can be described as curved, with the benzene rings lying on the same side of the mol­ecule [dihedral angle = 62.8 (4)°]. The conformation about the imine bond [1.294 (7) Å] is E. In the crystal, a two-dimensional array in the ab plane is mediated by O—H⋯O and N—H⋯O hydrogen bonds as well as C—H⋯Cl inter­actions. The layers stack along the c-axis direction, being connected by C—H⋯.π contacts

tert-Butyl N-((1S)-2-hy­droxy-1-{N′-[(1E)-4-meth­oxy­benzyl­idene]hydrazinecarbon­yl}eth­yl)carbamate

The mol­ecule of the title compound, C16H23N3O5, is twisted about the chiral C atom, the dihedral angle formed between the amide residues being 79.6 (3)°. The conformation about the imine bond [1.278 (5) Å] is E. In the crystal, O—H⋯O and N—H⋯O hydrogen bonding between the hy­droxy, amine and carbonyl groups leads to the formation of supra­molecular layers, which stack along the c-axis direction

Crystal Structure of the Chiral Azomethine Imine, (Z)-(S)-4-(tert-Butylcarbonylamino)-2-(2-methoxybenzylidene)-5-oxopyrazolidin-2-ium-1-ide, Obtained by the Cyclization of tert-Butyl (S)-2-[2-(methoxybenzylidene)hydrazine]-1-(hydroxymethyl)-2-oxocarbamate

Open Access via Springer Compact Agreement. The use of the NCS crystallographic service at Southampton and the valuable assistance of the staff there are gratefully acknowledged. JLW thanks FAPERJ and CNPq, Brazil for support.Peer reviewedPublisher PD

Benzyl N-(1-{N′-[(E)-2,3-dihy­droxy­benzyl­idene]hydrazinecarbon­yl}-2-hy­droxy­eth­yl)carbamate dihydrate

The organic mol­ecule in the title dihydrate, C18H19N3O6·2H2O, adopts a twisted U-shape with the major twists evident about the chiral C atom [the C—N—C—C torsion angle is −88.2 (4) °] and about the oxygen–benzyl bond [C—O—C—C = 74.2 (4) °]. The conformation about the imine bond [1.290 (4) Å] is E and an intra­molecular O—H⋯N hydrogen bond helps to establish the near coplanarity of the hy­droxy­benzene and hydrazine groups. The crystal packing features O—H⋯O and N—H⋯O hydrogen bonds, leading to two-dimensional supra­molecular arrays in the ab plane with weak C—H⋯π connections between the arrays

Benzyl N-[(S)-2-hy­droxy-1-({[(E)-2-hy­droxy-4-meth­oxy­benzyl­idene]hydrazin­yl}carbon­yl)eth­yl]carbamate

The shape of the title compound, C19H21N3O6, is curved with the conformation about the imine bond [1.291 (3) Å] being E. While the hy­droxy-substituted benzene ring is almost coplanar with the hydrazinyl residue [N—N—C—C = 177.31 (18)°], an observation correlated with an intra­molecular O—H⋯N hydrogen bond leading to an S(6) ring, the remaining residues exhibit significant twists. The carbonyl residues are directed away from each other as are the amines. This allows for the formation of O—H⋯O and N—H⋯O hydrogen bonds in the crystal, which lead to two-dimensional supra­molecular arrays in the ac plane. Additional stabilization to the layers is afforded by C—H⋯π inter­actions

tert-Butyl N-{(1S)-1-[(2,4-dihy­droxy­benzyl­idene)hydrazinecarbon­yl]-2-hy­droxy­eth­yl}carbamate ethanol monosolvate

The mol­ecule of the title ethanol solvate, C15H21N3O6·C2H6O, adopts a curved shape; the conformation about the imine bond [N=N = 1.287 (3) Å] is E. The amide residues occupy positions almost orthogonal to each other [dihedral angle = 85.7 (2)°]. In the crystal, a network of O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds leads to the formation of supra­molecular arrays in the ab plane with the ethanol mol­ecules lying to the periphery on either side. Disorder in the solvent ethanol mol­ecule was evident with two positions being resolved for the C atoms [site occupancy of the major component = 0.612 (10)]

Biopolymeric materials used as nonviral vectors: a review

Bacterial transformation and gene transfection can be understood as being the results of introducing specific genetic material into cells, resulting in gene expression, and adding a new genetic trait to the host cell. Many studies have been carried out to investigate different types of lipids and cationic polymers as promising nonviral vectors for DNA transfer. The present study aimed to carry out a systematic review on the use of biopolymeric materials as nonviral vectors. The methodology was carried out based on searches of scientific articles and applications for patents published or deposited from 2006 to 2020 in different databases for patents (EPO, USPTO, and INPI) and articles (Scopus, Web of Science, and Scielo). The results showed that there are some deposits of patents regarding the use of chitosan as a gene carrier. The 16 analyzed articles allowed us to infer that the use of biopolymers as nonviral vectors is limited due to the low diversity of biopolymers used for these purposes. It was also observed that the use of different materials as nonviral vectors is based on chemical structure modifications of the material, mainly by the addition of cationic groups. Thus, the use of biopolymers as nonviral vectors is still limited to only a few polysaccharide types, emphasizing the need for further studies involving the use of different biopolymers in processes of gene transfer.info:eu-repo/semantics/publishedVersio

Equivalência farmacêutica e bioequivalência de medicamentos: revisando conceitos e qualidade

Introduction: Safety, efficacy and quality of medicines are important for achieving the desired therapeutic effect, especially after 1999 when the Generic Act comes into force. Pharmaceutical equivalence and bioequivalence tests are essential for the production of generic medicines and since they have ensured the efficacy of the medicines compared to the reference medicines. Methods: A review of the literature was carried out from researches of scientific works in PubMed, Scielo and Google Scholar databases, using as keywords: pharmaceutical equivalence and bioequivalence. Development: The importance of pharmaceutical equivalence tests and bioequivalence was reported by the authors, especially when it comes to generic and / or similar drug analyzes. Pharmaceutical equivalence between two drugs is carried out by physical and physical-chemical analysis, indicating the presence of the same active principle, dose, pharmaceutical form, as well as route of administration. However, such testing does not always imply therapeutic equivalence, since differences in the excipients used and the production processes may lead to a change in the action of the drug in the body. For this, the bioequivalence test evaluates the bioavailability of drugs in different drugs, classifying them as bioequivalents when they present equivalent effects after administration of the same dose. Conclusion: The acceptance of generic and similar drugs by the population is still questioned, which may be a reflection of the quality deviations found in bioequivalence tests.Introdução: Segurança, eficácia e qualidade dos medicamentos são importantes para a obtenção do efeito terapêutico desejado, principalmente após 1999 quando entrou em vigor a Lei do Genérico. Os testes de equivalência farmacêutica e bioequivalência são primordiais para a produção de medicamentos genéricos e similares, uma vez que asseguraram a eficácia desses medicamentos comparados aos medicamentos de referência. Métodos: A revisão de literatura foi realizada a partir da busca de trabalhos científicos nas bases de dados PubMed, Scielo, Google Scholar, utilizando as palavras-chave: equivalência farmacêutica e bioequivalência. Desenvolvimento: A importância dos testes de equivalência farmacêutica e bioequivalência foi relatada pelos autores, principalmente quando se trata de análises de medicamentos genéricos e/ou similares. Equivalência farmacêutica entre dois medicamentos é realizada por meio de análises físicas e físico-químicas, indicando a presença do mesmo princípio ativo, dose, forma farmacêutica, bem como, via de administração. No entanto, tal teste nem sempre implica em equivalência terapêutica, uma vez que, divergências quanto aos excipientes utilizados e os processos de produção pode acarretar alteração na ação do fármaco no organismo. Para isso, o teste de bioequivalência avalia a biodisponibilidade dos fármacos em medicamentos diferentes, classificando-os como bioquivalentes quando apresentarem efeitos equivalentes após a administração da mesma dose. Conclusão: A aceitação dos medicamentos genéricos e similares pela população ainda é questionada, o que pode ser reflexo dos desvios de qualidade encontrados em testes de bioequivalência