18181-93-6Relevant academic research and scientific papers
Designing Dihydrofolate Reductase Inhibitors as X-ray Radiosensitizers to Reverse Radioresistance of Cervical Cancer
Liang, Yuanwei,Zeng, Delong,You, Yuanyuan,Ma, Bin,Li, Xiaoling,Chen, Tianfeng
, p. 1421 - 1428 (2020)
X-ray radiotherapy has been widely used in the treatment of cervical cancer, a common gynecologic malignant tumor. However, the therapeutic efficacy tends to be indistinctive. One major reason for this is amplification of the dihydrofolate reductase (DHFR) gene, which causes an increase in DHFR activity and attenuation of the treatment effect. To solve this problem, we synthesized a series of DHFR inhibitors derived from methotrexate (MTX) analogues as radiotherapy sensitizers. Activity screening revealed that compound 2a exerted the best inhibitory effect toward DHFR activity. In combination with X-ray radiotherapy (4 Gy), 2a showed much more prominent antiproliferative activity on cervical cancer cells than 2a or X-rays alone and revealed higher selectivity and radiosensitization than MTX. In vitro experiments showed that 2a + X-rays significantly induced cell apoptosis, as revealed by the increase in the Sub-G1 population and activation of caspase 3, 8, and 9. The in vivo antitumor effect demonstrated that in the presence of X-rays, 2a effectively suppressed tumor growth and did not cause obvious side effects. In conclusion, as a DHFR inhibitor, 2a successfully reversed the radioresistance problem induced by radiotherapy and greatly promoted the therapeutic effect. This is a promising candidate for tumor treatment that deserves further research and development. This study clearly demonstrates that DHFR inhibitors could be developed as promising radiosensitizers in the treatment of cervical cancer and that further research to improve their activity and potential in future clinical use is deserved.
Pteridines. Part CXIII. Protection of Pteridines
Yao, Qizheng,Pfleiderer, Wolfgang
, p. 1 - 12 (2007/10/03)
The low solubulity of pterins can drastically be improved by N2-acylation or formation of the N2-[(dimethylamino)methylene] derivatives. Both types of compounds can be alkylated under Mitsunobu conditions to form from N2-acylpterins (see 2 and 3) and their derivatives (see 5, 6, 8, 9, 11, 13, 15, and 17) selectively the O4-alkyl derivatives 22-31, whereas the electron-donating [(dimethylamino)methyleneamino] function in 46-51 gives, in a selective reaction, the N(3)-substitution (->52-61). N2,N2-Dimethylpterins and 18 and 19 and N2-methylpterins 20 and 21 direct alkylation also to the O4-position (->32-35, 38 and 39). Deacylation can be achieved under very mild conditions by solvolysis with MeOH (22->40, 26->41), and displacement of the O4-[2-(4-nitrophenyl)ethyl] group proceeds with ammonia at room temperature to the corresponding pteridin-2,4-diamine 42-45. Cleavage of the N2-[(dimethylamino)methylene] group works well with ammonia (->62-67). The advantage of applying the 2-(4-nitrophenyl)ethyl (npe) group as blocking group is seen in its selective removal by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) under aprotic conditions without harming the other substituents.
PROTECTION AND DEPROTECTION OF FUSED 2-AMINO-4(3H)PYRIMIDONES: CONVERSION OF PTERINS AND 5-DEAZAPTERINS TO 2,4-DIAMINO DERIVATIVES
Taylor, Edward C.,Otiv, S. R.,Durucasu, Inci
, p. 1883 - 1895 (2007/10/02)
5-Deazapterins and pterins are readily converted to their 4-deoxy-4-amino derivatives (a lactam-to-amidine conversion) by reaction with 4-chlorophenyl phosphorodichloridate and 1,2,4-triazole to give intermediate 4- derivatives, followed by reaction with aqueous ammonia.Some anomalous results obtained by application of the Mitsunobu reaction (normally a lactam-to-lactim ether conversion) to 5-deazapterins are detailed.
