This compound was needed for some research into the mechanisms of rearrangements. We can disconnect on either side of the ether oxygen atom, but (b) is much better because (a) does not correspond to a reliable reaction: it might be hard to control selective alkylation of the primary hydroxyl group in the presence of the secondary one.

You might think that the best reagent to use as the equivalent of the synthon B would be bromide C. Be more ingenious! A much better solution is to use the epoxide D. Nucleophilic attack on the less hindered terminal carbon atom of the epoxide gives us the type of com pound we want, and this was how the target molecule was made. In using the epoxide we have gone one step beyond all the disconnections we have talked about so far because we have used one functional group to help disconnect another—in other words, we noticed the alcohol adjacent to the ether we wanted to disconnect and managed to involve them both in the disconnection. Such disconnections are known as two-group disconnections, and you should always be on the look-out for opportunities of using them because they are an efficient way of getting back to simple starting materials. We call this epoxide disconnection a 1,2-disconnection because the two functional groups in the two-group disconnection are in a 1,2-relationship.

Drug molecules often have 1,2-related functional groups: 2-amino alcohols form one important class. Phenyramidol, for example, is a muscle relaxant. A simple two-group disconnection takes it straight back to 2-amino pyridine and styrene oxide.

Notice that we have written ‘1,2-diX’ above the arrow to show that it’s a two-group (‘diX’) disconnection—we’ve also numbered the carbon atoms in the starting material to show the 1,2-relationship. It may seem trivial in such a simple example, but it’s a useful part of the process of writing retrosynthetic analyses because it helps you to spot opportunities for making two-group disconnections.

اخر الاخبار

اخبار العتبة العباسية المقدسة

جمعية كشافة الكفيل: المجالس الحسينية تعلّم الفتية قيم نهضة الإمام الحسين (عليه السلام)

عَبرَ المجالس الحسينية.. المجمَع العلمي يقدّم محاضرات دينية وتلاوات قرآنية في بغداد والنجف وميسان

برعاية العتبة العباسية المقدسة.. موكب قناديل السماء يُحيي مراسم اليوم الثالث عشر من المحرّم

بعد انتهاء مراسم ذكرى دفن الأجساد الطاهرة قسم رعاية الصحن يباشر بحملة تنظيف واسعة لصحن مرقد أبي الفضل العباس (عليه السلام)

المزيد

الآخبار الصحية

لكبح الجوع وخسارة الوزن.. "سر بسيط" في نظام جوكوفيتش ؟

هل يساعد الرجيم في علاج الأمراض العقلية؟

لحماية أسنان طفلك.. هذا الفيتامين يقلل خطر التسوس

أكل الطعام بسرعة.. طريق سريع إلى أمراض خطيرة

المزيد

الآخبار التكنلوجية

ما هي أفضل درجة حرارة لتكييف الهواء في السيارة؟

ذوبان الأنهار الجليدية يوقظ "عمالقة نائمة"!

9 يوليو يشهد أقصر يوم في التاريخ المسجل ؟!!

راتبه عشرات ملايين الدولارات.. زوكربرغ يخطف "عقل أبل"

المزيد

مواضيع ذات صلة

1,2-Disconnections

Amine synthesis using functional group interconversions

Functional group interconversion

Multiple step syntheses: avoid chemoselectivity problems

Choosing a disconnection

Synthons are idealized reagents

Disconnections must correspond to known, reliable reactions

Synthons are idealized reagents

The E-selective Wittig reaction

The Z-selective Wittig reaction

The Peterson reaction is stereospecific

The one-step Julia olefination