Studies in 2-Naphthol Derivatives

This thesis consists of two sections. The first section deals with the sodium hydroxide induced rearrangement of l-methyl-2-bromo-3H-naphtho (2,1-b) pyran-3-one. This reaction had already been studied by Dey and Lakshminarayanan, who identified the products as 2-(2-hydroxynaphth-l-yl) propanal and 1-methylnaphtho (2,1-b) furan-2-carboxylic acid: The naphthylpropanal would be a useful starting material for the synthesis of l-alkyl-2-naphthols, so we attempted to repeat this rearrangement. When the Indians' conditions were followed, no clean and tractable products resulted. Air oxidation and dehydration of the initial products seemed to occur. The reaction and work-up were therefore performed under nitrogen and acidification of the reaction mixture was done with carbon dioxide. Under these conditions, two products were isolated. The main product (78%) is 1-(2-hydroxynaphth-1-yl) propan-2-one. The minor product (7%) is 2-methylnaphtho (2,1-b) furan-1-carboxylic acid: These structure assignments are supported by elemental analyses, full spectral data and chemical transformations on both products. A critical review of Dey's published evidence suggests that he had isolated the same products as we did, but assigned an erroneous structure to each as a result of inadequate spectral evidence, uncritical interpretation of chemical evidence and over-reliance on analogies. Mechanisms for the displacement of halides from sp2 hybridised carbons, in a-halolactones and in related systems is reviewed in the Introduction. From this large group of reactions, only the formation of Feist's acid from 2-bromo-4,6-dimethy 1-5-ethoxycarbonylpyrone seems to bear any similarity to the aryl shift wo observe with the methylbromonaphthopyran. The unique occurrence of this rearrangement in this compound is rationalised in terms of the steric congestion due to the methyl group in this particular bromopyrone. The second section deals with synthesis and epoxidation of various 2(1H) naphthalenones. 1-Hydroxy-1-isopropyl-2(1H) naphthalenone has been reported to give on treatment with Na2CO3/H2O2 in aqueous ethanol only one epoxide (90% yield) with the epoxide oxygen on the opposite face (trans) to the hydroxyl group. The same author also reported the 1-acetoxyl analogue to yield the trans epoxide exclusively. There are relatively few such cases of stereospecific epoxidation of dissymmetric enones in the literature and the factors controlling which face of the enone is epoxidised are not all understood. Leppards epoxidations were repeated and the reported results confirmed, save that the 1-acetoxyl compound underwent substantial hydrolysis of the acetoxyl group (only 36% of a single acetoxy-epoxide was isolated). In order to explore the structural requirements for this steric control a range of 2(1H) naphthalenones with different alkyl and oxygen-containing functions on C was made. In addition to the two compounds already mentioned, 2(1H) naphthalenones bearing the following pairs of substituents on C were successfully synthesised: methyl and hydroxyl; methyl and acetoxyl; methyl and methoxyl; ethyl and acetoxyl; isopropyl and trimethylsilyloxyl. Attempts to synthesise and isolate the compound bearing isopropyl and methoxyl on C by alkylation of the 1-hydroxyl compound were unsuccessful. Epoxidation with alkaline hydrogen peroxide of 1-acetoxy-1-methyl-2(lH) naphthalenone and 1-isopropyl-1-trimethylsilyloxy-2(1H) naphthalenone led to the complete hydrolysis of the acetoxyl and trimethylsilyloxyl groups respectively. The epoxide isolated in both cases was the same as that from 1-hydroxy-1-alkyl-2(1H) naphthalenone. Epoxidation of 1-hydroxy-1-methy1-2(1H) naphthalenone and of 1-methoxy-1-methyl-2 (1H) naphthalenone gave one simple epoxide in each case (assumed trans). The 1-hydroxy-1-methyl compound also gave a material which seemed to be a dimer of the simple epoxide. Although in all cases studied only one stereoisomer was formed in the epoxidations it was difficult to prove its stereochemistry. 13C and lanthanide shifts of 1H NMR spectra were studied but no conclusions could be drawn from them about the stereochemistry of the epoxides. The Introduction consists of a selected survey of published examples of epoxidations and related processes in which stereoselective product formation took place. In some cases this outcome might have been anticipated, and in others not. A critical examination of the explanations given does not appear to reveal any underlying unity of cause

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival