Stereochemical aspects in the synthesis of novel N-(purin-6-yl)dipeptides as potential antimycobacterial agents

The synthesis of purine conjugates with natural amino acids is one of the promising directions in search for novel therapeutic agents, including antimycobacterial agents. The purpose of this study was to synthesize N-(purin-6-yl)dipeptides containing the terminal fragment of (S)-glutamic acid. To obtain the target compounds, two synthetic routes were tested. The first of them is based on coupling of N-(purin-6-yl)-(S)-amino acids to dimethyl (S)-glutamate in the presence of carbodiimide coupling agent followed by the removal of ester groups. However, it turned out that this coupling process was accompanied by racemization of the chiral center of N-(purin-6-yl)-α-amino acids and in all cases led to mixtures of (S,S)- and (R,S)-diastereomers (6:4). Individual (S,S)-diastereomers were obtained using an alternative approach based on the nucleophilic substitution of chlorine in 6-chloropurine or 2-amino-6-chloropurine with corresponding dipeptides as nucleophiles. The enantiomeric purity of the target compounds was confirmed by chiral HPLC. To test the assumption that racemization of the chiral center of N-(purin-6-yl)-α-amino acids occurs with the participation of nitrogen atoms of the imidazole ring via the stage of formation of a chirally labile intermediate, we obtained such structural analogs of N-(purin-6-yl)-(S)-alanine as N-(9-benzylpurin-6-yl)-(S)-alanine and N-(7-deazapurin-6-yl)-(S)-alanine. It was found that coupling of these compounds to dimethyl (S)-glutamate was also accompanied by racemization. This indicates that the imidazole fragment does not play a crucial role in this process. When testing the antimycobacterial activity of some of the obtained compounds, conjugates with moderate activity against the laboratory Mycobacterium tuberculosis H37Rv strain (MIC 3.1–6.25 μg/mL) were identified. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, AT part of Springer Nature.The work was financially supported by the Russian Science Foundation (Grant 19-13-00231). We are grateful to Dr. Marionella A. Kravchenko [Ural Research Institute of Phthisiopulmonology (National Medical Research Center, Ministry of Healthcare of the Russian Federation, Ekaterinburg, Russia)] for conducting biological trials. Analytical studies were carried out using equipment of the Centre for Joint Use ?Spectroscopy and Analysis of Organic Compounds? at the Postovsky Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences

Young people in HIV care in Ukraine: a national survey on characteristics and service provision [version 1; peer review: 2 approved]

Background: Ukraine’s perinatally HIV-infected (PHIV) young people are ageing into adolescence/young adulthood and, alongside those with behaviourally-acquired infections (BHIV), require transitional and other support services. We aimed to map this population and policies/ service provision at specialist HIV centres, to inform future service development. Methods: A national survey was conducted of 28 HIV/AIDS centres on number, characteristics (age group, HIV acquisition mode) and care setting (paediatric/adult) of 10-24 year olds in HIV care in each of 24 regions in January 2016. Information was collected on policies/ service provision at each centre. Results: Of 13,286 young people aged 10-24 years registered for HIV care nationally in Ukraine in January 2016, 1,675 were aged 10-18 years. Three-quarters of ≤19 year olds were PHIV, while 72% of 20-24-year-olds had sexually-acquired infection. Five regions accounted for two-thirds of 10-18 year olds in paediatric and 85% of 19-24 year olds in adult services. In 2015, 97 young people transitioned from paediatric to adult services nationally, typically at 18 years although with flexibility in timing at 17/28 centres. At 27/28 centres, BHIV young people aged <18 years began their HIV care in paediatric services sometimes (5) or always (22). Transition support most commonly consisted of a joint appointment with paediatrician and adult doctor, and support from a psychologist/social worker (both at 24/28 centres). Only 5/28 centres offered routine HIV care during the evening or weekend, and availability of integrated sexual/reproductive health and harm reduction services was uneven. Of 16/28 centres selectively following-up patients who did not attend for care, 15 targeted patients in paediatric services. Conclusions: Heterogeneity in the population and in service availability at the main regional/municipal HIV/ AIDS centres has implications for potential structural barriers to HIV care, and development of services for this group

Synthesis and Assessment of Antiplatelet and Antithrombotic Activity of 4-Amino-Substituted 5-Oxoproline Amides and Peptides

Venous thromboembolism is a serious problem because it significantly increases the risk of developing vascular complications in elderly patients with obesity or immobilization, cancer, and many other diseases. Thus, there is a need to study new therapeutic strategies, including new medicinal agents for the efficient and safe correction of thrombus disorders. In this work, we have synthesized a number of new amides and peptides of 4-amino-5-oxoprolines and studied their antiplatelet and antithrombotic activity in experiments in vitro and in vivo. It has been found that the newly obtained compounds slow down the process of thrombus formation in a model of arterial and venous thrombosis, without affecting plasma hemostasis parameters. (2S,4S)-4-Amino-1-(4-fluorophenyl)-5-oxoprolyl-(S)-phenylalanine proved to be the most efficient among the studied derivatives. The results obtained indicate the advisability of further studies on 5-oxoproline derivatives in order to design pharmaceutical agents for the prevention and treatment of the consequences of thrombosis. © 2023 by the authors.Ministry of Science and Higher Education of the Russian Federation: 075-15-2020-777This research was funded by the Ministry of Science and Higher Education of Russia (agreement no. 075-15-2020-777 of 1 October 2020)

Anxiety symptoms and felt stigma among young people living with perinatally or behaviourally-acquired HIV in Ukraine: A cross-sectional survey

BACKGROUND: Ukraine has the second largest European HIV epidemic. This study aimed to describe stigma, demographic and social factors and their association with anxiety among perinatally and behaviourally-HIV-infected (PHIV; BHIV) young people in Kiev and Odessa. METHODS: 104 PHIV and 100 BHIV young people aged 13-25 years completed a confidential tablet-based survey. Survey tools included the Hospital Anxiety and Depression Scale (HADS) (anxiety sub-scale scores of 8-10 indicating mild and ≥11 moderate/severe symptoms in last 7 days), Rosenberg Self-Esteem Scale (RSES) and HIV Stigma Scale (HSS) (short version, composite of disclosure, negative self-image and public attitudes sub-scales). Unadjusted Poisson regression models were fitted to explore factors associated with moderate/severe anxiety symptoms. RESULTS: PHIV and BHIV young people were of median age 15.5 [IQR 13.9-17.1] and 23.0 [21.0-24.3] years, having registered for HIV care a median 12.3 [10.3-14.4] and 0.9 [0.2-2.4] years previously; 97% (97/100) and 66% (65/99) respectively were on ART. Overall 43% (95%CI 36-50%) reported any and 13% (95%CI 9-19%) moderate/severe anxiety symptoms, with no difference by HIV acquisition mode (p = 0.405) or gender (p = 0.700). 42% (75/180) reported history of an emotional health problem for which they had not been referred/attended for care. Moderate/severe anxiety symptoms were associated with HIV-related stigma (prevalence ratio (PR) 1.24 95%CI 1.14-1.34 per HSS unit increase), lower self-esteem (PR 0.83 95%CI 0.78-0.90 per RSES point increase), CD4 ≤350 cells/mm3 (PR 2.29 95%CI 1.06-4.97), having no-one at home who knew the respondent's HIV status (PR 9.15 95%CI 3.40-24.66 vs all know) and, among BHIV, less stable living situation (PR 6.83 95%CI 1.99-23.48 for ≥2 vs no home moves in last 3 years) and history of drug use (PR 4.65 95%CI 1.83-11.85). CONCLUSIONS: Results indicated unmet need for psychosocial support. Further work is needed to explore strategies for mental health support, particularly around disclosure, self-esteem and stigma

Track E Implementation Science, Health Systems and Economics

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138412/1/jia218443.pd