The next compound was an intermediate in the synthesis of the potential anti-obesity drug ICI-D7114. You can spot that, with two ethers and an amine functional group, it requires several disconnections to take it back to simple compounds. The question is, which do we do first? One way to solve the problem is to write down all the possibilities and see which looks best. Here there are four reasonable disconnections: one at each of the ether groups (a and b) or on either side of the amine (c and d).

Both (a) and (b) pose problems of chemoselectivity as it would be hard to alkylate the phenol in the presence of the basic nitrogen atom. Between (c) and (d), (c) appears to be the better choice because the next disconnection after (d) will have to be an alkylation of O in the presence of an NH₂ group. To avoid chemoselectivity problems like this, we want to try to intro duce reactive groups late in the synthesis. In terms of retrosynthetic analysis, then, we can formulate another guideline.

●Guideline 3 Consider alternative disconnections and choose routes that avoid chemoselectivity problems— often this means disconnecting reactive groups first.

This guideline helps us in the next retrosynthetic step for the ICI-D7114 intermediate. Disconnection (c) gave us a compound with two ethers that might be disconnected further by disconnection (e) or (f).

Disconnection (e) requires alkylation of a compound that is itself an alkylating agent. Disconnection (f) is much more satisfactory and leads to a compound that is easily disconnected to 4-hydroxyphenol and 1,2-dibromoethane. Using Guideline 3, we can say that it’s best to disconnect the bromoethyl group (f) before the benzyl group (g) because the bromo ethyl group is more reactive and more likely to cause problems of chemoselectivity.

اخر الاخبار

اخبار العتبة العباسية المقدسة

قسم العلاقات العامة يختتم فعاليات محطات فتية الكفيل الثقافية في محافظة نينوى

ما الخدمات التي قدّمها موكب أشبال الطفّ لزائري عاشوراء؟

العتبة العباسية المقدسة تنظّم مسيرات عزائية لإحياء ذكرى عاشوراء في نينوى

قسم الشؤون الفكرية يحيي ذكرى استشهاد الإمام الحسين (عليه السلام) في القارة الإفريقية

المزيد

الآخبار الصحية

تناول الجبن.. مفيد للجسم أم خطر يهدد صحتك؟

طبيبة أسنان تحذر.. لا تتجاهل هذه العلامة بعد التنظيف

يجب أن تأكل المزيد من الشمام هذا الصيف.. إليك السبب ؟

تأثير صحي كبير.. كم بيضة يجب أن تتناول يوميا؟

المزيد

الآخبار التكنلوجية

أداء خلايا البيروفسكايت الشمسية تحت الماء قد يزيد كفاءة تحويل الكهرباء

مسافة الأمان: أساس القيادة الآمنة وتجنب الحوادث

هل القيادة السريعة تعني استهلاك اكثر للوقود؟

لماذا يعتبر كوكب المريخ غير صالح للحياة؟

المزيد

مواضيع ذات صلة

E-selective reduction of alkynes using sodium in liquid ammonia

Amine synthesis using functional group interconversions

Functional group interconversion

Synthons are idealized reagents

The E-selective Wittig reaction

The Z-selective Wittig reaction

Stereoselectivity in the Wittig reaction depends on the ylid

The Peterson reaction is stereospecific

The one-step Julia olefination

The Julia olefi nation is stereoselective

The Julia olefination is regiospecific and connective

Sulfoxide elimination—oxidation to enones