JP3837876B2 - Azidohalogenobenzyl derivatives and methods for protecting hydroxyl groups - Google Patents

Description

【０００７】
（式中、Ａはハロゲン原子を、Ｂはハロゲン原子又は水素原子を、及びＸは水酸基と反応しうる基を示す）で表されるアジドハロゲノベンジル誘導体〔以下、アジドハロゲノベンジル誘導体（Ｉ）という〕。
【０００８】
(2) 一般式（Ｉ）において、Ｘがハロゲン原子又はイミドイルオキシ基を示す(1) 記載のアジドハロゲノベンジル誘導体。
【０００９】
(3) 一般式（Ｉ）において、Ｂが水素原子を示し、Ｘがハロゲン原子を示す(1) 記載のアジドハロゲノベンジル誘導体。
【００１０】
(4) ４−アジド−３−クロロベンジルブロマイドである(1) 記載のアジドハロゲノベンジル誘導体。
【００１１】
(5) 少なくとも１個の水酸基の水素原子が、一般式（ＩＩ）
【００１２】
【化８】

【００１３】
（式中、各記号は前記と同義である）で表されるアジドハロゲノベンジル基〔以下、アジドハロゲノベンジル基（ＩＩ）という〕に置換されてなる糖化合物。
【００１４】
(6) 単糖、オリゴ糖又は多糖を、アジドハロゲノベンジル誘導体（Ｉ）と反応させて得られる(5) 記載の糖化合物。
【００１５】
(7) アジドハロゲノベンジル誘導体（Ｉ）と水酸基含有化合物とを反応させて、該水酸基含有化合物の水酸基の水素原子をアジドハロゲノベンジル基（ＩＩ）に置換することを特徴とする水酸基の保護方法。
【００１６】
(8) 水酸基含有化合物が糖構造を含有する化合物である(7) 記載の保護方法。
【００１７】
(9) アジドハロゲノベンジル誘導体（Ｉ）を含有する、水酸基を保護するための試薬。
【００１８】
(10)一般式（Ｉ）において、Ｘがハロゲン原子又はイミドイルオキシ基を示す(9) 記載の試薬。
【００１９】
(11)一般式（Ｉ）において、Ｂが水素原子を示し、Ｘがハロゲン原子を示す(9) 記載の試薬。
【００２０】
(12)アジドハロゲノベンジル誘導体（Ｉ）が４−アジド−３−クロロベンジルブロマイドである(9) 記載の試薬。
【００２１】
【発明の実施の形態】
本発明において、各置換基の定義は以下の通りである。
ハロゲン原子としては、フッ素原子、塩素原子、臭素原子、ヨウ素原子が挙げられ、塩素原子、臭素原子が好ましい。より好ましくは塩素原子である。
水酸基と反応しうる基とは、水酸基と反応して該水酸基の水素原子と共に脱離しうる基であって、例えば上記のようなハロゲン原子、イミドイルオキシ基等が挙げられる。好ましくはハロゲン原子である。
ここで、イミドイルオキシ基とは、炭素数１〜５個のアルキル基等を有するイミドイルオキシ基であって、更に置換基としてハロゲン原子等を有していてもよい。具体的には１，１，１−トリクロロエタンイミドイルオキシ基等が挙げられる。
【００２２】
本発明のアジドハロゲノベンジル誘導体（Ｉ）として、好ましくは４−アジド−３−クロロベンジルブロマイドが挙げられる。
【００２３】
本発明のアジドハロゲノベンジル誘導体（Ｉ）は、例えばＸがハロゲン原子の場合、以下のようにして合成することができる。
【００２４】
【化９】

【００２５】
（式中、Ｘ¹ はハロゲン原子を示し、Ａ及びＢは前記と同義である）
即ち、一般式（ＩＩＩ）で表されるアミノハロゲノトルエン〔以下、アミノハロゲノトルエン（ＩＩＩ）という〕を塩酸水溶液中、亜硝酸ナトリウムで処理し、次いでアジ化ナトリウムで処理することにより一般式（ＩＶ）で表されるアジドハロゲノトルエン〔以下、アジドハロゲノトルエン（ＩＶ）という〕を得る〔新実験化学講座ＸＶＩ・有機化合物の合成と反応 III，丸善，1665-1666 頁（１９７８）〕。さらにこれを、例えば２，２’−アゾビスイソブチロニトリル（ＡＩＢＮ）等の触媒の存在下、適当な溶媒中、必要に応じて不活性ガス気流中、遮光下に、Ｎ−ハロゲノスクシンイミドと反応させることにより、本発明のアジドハロゲノベンジル誘導体（Ｉ）を得ることができる〔新実験化学講座ＸＶＩ・有機化合物の合成と反応Ｉ，丸善，336-339 頁（１９７９）〕。
また、Ｎ−ハロゲノスクシンイミドの代わりに、塩素ガス、臭素ガス等のハロゲンガス、又は固体ヨウ素や液体臭素のような固体若しくは液体のハロゲンを用いてもよい。
【００２６】
アジドハロゲノトルエン（ＩＶ）の合成は、通常、アミノハロゲノトルエン（ＩＩＩ）に対して１〜１０当量、好ましくは１〜５当量、より好ましくは１〜２当量の亜硝酸ナトリウムを加え、−１０℃〜室温で数分〜数十分間攪拌した後、アミノハロゲノトルエン（ＩＩＩ）に対して１〜５当量、好ましくは１〜２当量のアジ化ナトリウムを加えてさらに−１０℃〜室温で数分〜数十分間攪拌することにより行われる。
【００２７】
出発原料であるアミノハロゲノトルエン（ＩＩＩ）としては、例えば２−アミノ−４−フルオロトルエン、２−アミノ−５−フルオロトルエン、２−アミノ−６−フルオロトルエン、３−アミノ−４−フルオロトルエン、３−アミノ−５−フルオロトルエン、３−アミノ−６−フルオロトルエン、４−アミノ−２−フルオロトルエン、４−アミノ−３−フルオロトルエン、２−アミノ−３−クロロトルエン、２−アミノ−５−クロロトルエン、２−アミノ−６−クロロトルエン、３−アミノ−４−クロロトルエン、３−アミノ−６−クロロトルエン、４−アミノ−２−クロロトルエン、４−アミノ−３−クロロトルエン、２−アミノ−５−ブロモトルエン、２−アミノ−６−ブロモトルエン、２−アミノ−５−ヨードトルエン、４−アミノ−２−ヨードトルエン、４−アミノ−２，６−ジクロロトルエン、２−アミノ−４，６−ジクロロトルエン、４−アミノ−２，５−ジクロロトルエン等が挙げられる。
【００２８】
アジドハロゲノトルエン（ＩＶ）とＮ−ハロゲノスクシンイミドとの反応においては、通常、アジドハロゲノトルエン（ＩＶ）に対して１〜５当量、好ましくは１〜２当量のＮ−ハロゲノスクシンイミドが用いられる。反応に用いられる溶媒としては、例えばベンゼン、トルエン、キシレン等の芳香族炭化水素やジクロロメタン、ジクロロエタン等のハロゲン化炭化水素等が挙げられるが、これら溶媒は、無水状態のものを用いることが好ましい。反応温度は、通常使用する溶媒の沸点であり、反応時間は、通常数十分〜数十時間である。
【００２９】
用いられるＮ−ハロゲノスクシンイミドとしては、Ｎ−クロロスクシンイミド、Ｎ−ブロモスクシンイミド、Ｎ−ヨードスクシンイミド等が挙げられる。
【００３０】
また、Ｘがイミドイルオキシ基である場合には、例えば対応するアジドハロゲノベンジルアルコールを、ジクロロメタン等の溶媒中、水素化ナトリウムの存在下、トリクロロアセトニトリルと反応させる方法〔第４版 実験化学講座有機合成VIII，丸善，274-275 頁（１９９０）〕、又は対応するアジドハロゲノベンジルアルコールを、ジクロロメタン等の溶媒中、炭酸セシウムの存在下、トリクロロアセトニトリルと反応させる方法等、自体公知の合成方法によりアジドハロゲノベンジル誘導体（Ｉ）を得ることができる。
【００３１】
得られた本発明のアジドハロゲノベンジル誘導体（Ｉ）は水酸基含有化合物の水酸基を保護するのに有用である。
水酸基含有化合物は糖構造を含有する化合物を包含する。
糖構造を含有する化合物を本発明のアジドハロゲノベンジル誘導体（Ｉ）と反応させることにより、該化合物の水酸基の水素原子がアジドハロゲノベンジル基（ＩＩ）に置換されてなる糖化合物が得られる。
【００３２】
糖構造を含有する化合物としては、具体的には単糖類（グルコース、アラビノース、フコース、ガラクトース、マンノース、キシロース、フルクトース、リキソース、アロース、アリノース、リボース、タロース、グロース、イドース、アルトロース、ソルビトール、マンニトール、グルコサミン等）、オリゴ糖類（マルトース、イソマルトース、ツラノース、ゲンチオビオース、メリビオース、プランテオビオース、プリメレロース、ビシアノース、ニゲロース、ラミナリビオース、ルチノース、セロビオース、キシロビオース、マルトトリオース、ゲンチアノース、メレチトース、プランテオース、ケトース、トレハロース、スクロース、ラクトース、ラフィノース、キシロトリオース等）、多糖類（アミロース、フィコール、デキストリン、デンプン、デキストラン、ポリデキストロース、プルラン、シクロデキストリン、グルコマンノグリカン、グルコマンナン、グアガム、アラビアゴム、グリコサミノグリカン等）、複合糖質（糖ペプチド、糖タンパク質、糖脂質、プロテオグリカン等）等が挙げられる。
また、これらの糖構造を含有する化合物の水酸基の一部が、例えばアセチル基、アセチルエチルカルボニル基、ベンゾイル基等のアシル基、例えばベンジル基、ニトロベンジル基、アジドベンジル基、メトキシベンジル基等の置換アルキル基等で保護されたものも本発明に係る糖構造を含有する化合物に含まれる。更に、これら糖構造を含有する化合物には、リンカーを介して、例えば樹脂やポリマー等に結合している糖構造を含有する化合物も含まれる。
【００３３】
少なくとも１個の水酸基の水素原子がアジドハロゲノベンジル基（ＩＩ）に置換されてなる糖化合物は、上記糖構造を含有する化合物をアジドハロゲノベンジル誘導体（Ｉ）と反応させることにより得られる。
該反応は、通常、Ｎ，Ｎ−ジメチルホルムアミド（ＤＭＦ）等の溶媒中、０℃〜室温で、数十分〜数時間攪拌することにより行われる。この際、水酸基の活性化の為に、例えば水素化ナトリウム等を用いることが好ましい。
【００３４】
少なくとも１個の水酸基の水素原子がアジドハロゲノベンジル基（ＩＩ）に置換されてなる糖化合物としては、例えばメチル ６−Ｏ−（４−アジド−３−クロロベンジル）−２，３，４−トリ−Ｏ−ベンジル−Ｄ−グルコピラノシド、メチル ４−Ｏ−（４−アジド−３−クロロベンジル）−２，３，６−トリ−Ｏ−ベンジル−Ｄ−グルコピラノシド等が挙げられる。
【００３５】
本発明の水酸基の保護方法は、アジドハロゲノベンジル誘導体（Ｉ）と水酸基含有化合物とを反応させて、該水酸基含有化合物の水酸基の水素原子をアジドハロゲノベンジル基（ＩＩ）に置換することにより行われる。
本発明に用いられる水酸基含有化合物としては、例えば上記のような糖構造を含有する化合物、或いはその糖構造を含有する化合物の糖構造を形成する環の酸素原子が硫黄原子やＣＨ₂ に置き換わったもの等が好ましく挙げられるが、当該水酸基含有化合物は上記のものに限定されるものではなく、水酸基を有する化合物であればいずれにてもよい。
【００３６】
アジドハロゲノベンジル誘導体（Ｉ）と水酸基含有化合物との反応は、上記アジドハロゲノベンジル誘導体（Ｉ）と糖構造を含有する化合物との反応に準じて行えばよい。
【００３７】
かくして得られた水酸基の保護基により、即ちアジドハロゲノベンジル基（ＩＩ）により保護された化合物は、例えばＹ．オイカワら，テトラヘドロン レター，２３，８８５頁（１９８２）等に記載の方法によって、穏和な条件下で容易に脱保護することができる。即ち、トリフェニルホスフィン（ＰＰｈ₃ ）をアジドハロゲノベンジル基（ＩＩ）に対して１〜５当量、好ましくは１〜２当量加えて攪拌し、更に水、酢酸及び２，３−ジクロロ−５，６−ジシアノベンゾキノン（ＤＤＱ）をアジドハロゲノベンジル基（ＩＩ）に対して１〜５当量、好ましくは１〜２当量加えて攪拌することによって、容易に保護基を脱離させることができる。また、酢酸の代わりにシリカゲルを用いてもよい。
【００３８】
【実施例】
以下、製造例、実験例及び実施例を挙げて本発明を更に詳細に説明するが、本発明はこれら実施例により何ら限定されるものではない。
【００３９】
製造例１：４−アジド−３−クロロトルエンの合成
４−アミノ−３−クロロトルエン(14.16 g, 0.1 mol)を、濃塩酸(50 ml) 、水(400 ml)及びＤＭＦ(100 ml)の混液に溶解し、氷−食塩水で冷却した。これに、亜硝酸ナトリウム(6.9 g, 0.1 mol)の水溶液(50 ml) を−５℃〜５℃で20分かけて滴下した。更に、10分間撹拌した後、アジ化ナトリウム(6.5 g, 0.1 mol)の水溶液(50 ml) を10℃〜20℃で20分かけて滴下した。反応溶液を更に1.5 時間攪拌した後、ジエチルエーテルで抽出した (150 ml×3)。エーテル層を合わせ、飽和重曹水、飽和食塩水で洗浄し、無水硫酸ナトリウムで乾燥した。減圧下、溶媒を除去し、17.14 g の表題化合物を褐色油状物として得た。
MS(EI): M⁺ = 167, 169
¹H-NMR(270MHz, CDCl₃ ) δ:7.19(d,1H), 7.06(m,2H), 2.31(s,3H)
【００４０】
実施例１：４−アジド−３−クロロベンジルブロマイドの合成
４−アジド−３−クロロトルエン(17.14 g, 0.1 mol)を無水ベンゼン(80 ml) に溶解し、Ｎ−ブロモスクシンイミド(19.6 g, 0.11 mol)及びＡＩＢＮ(1.64 g, 0.01 mol)を加え、遮光下、窒素気流中で１０時間還流した。水(100 ml)を加え、ろ過した。ろ液の水層をとり、エーテルで抽出した。有機層を合わせ、食塩水で洗浄し、無水硫酸ナトリウムで乾燥した。減圧下に溶媒を除去し、得られた褐色油状物をシリカゲルカラムクロマトグラフィー（溶離液；ヘキサン）で精製することにより、表題化合物を得た（14.2 g, 収率58％）。
融点：75〜77℃
¹H-NMR(270MHz, CDCl₃ ) δ:7.42(d,1H), 7.31(dd,1H), 7.14(d,1H), 4,42(s,2H)
【００４１】
実施例２：メチル ６−Ｏ−（４−アジド−３−クロロベンジル）−２，３，４−トリ−Ｏ−ベンジル−Ｄ−グルコピラノシドの合成
メチル ２，３，４−トリ−Ｏ−ベンジル−Ｄ−グルコピラノシド(1.16 g, 2.5 mmol)をＤＭＦ(10 ml) に溶解し、０℃で水素化ナトリウム(60%油中，120 mg, 3.00 mmol)を加え、15分間撹拌した。続いて、４−アジド−３−クロロベンジルブロマイド(740 mg, 3.00 mmol) を少しずつ加えた。０℃で30分間、室温で３時間撹拌後、反応溶液に氷水を加え、酢酸エチルで抽出した。減圧下に溶媒を除去し、得られた残渣をシリカゲルカラムクロマトグラフィー（溶離液；ヘキサン：酢酸エチル＝４：１）で精製することにより、表題化合物を黄色油状物として得た（1.48 g, 収率94％）。
¹H-NMR(270MHz, CDCl₃ ) δ:7.37-7.03(m,18H), 5.00-4.35(m,9H), 3.98(t,1H), 3.76-3.52(m,5H), 3.38(s,3H)
【００４２】
実施例３：メチル ４−Ｏ−（４−アジド−３−クロロベンジル）−２，３，６−トリ−Ｏ−ベンジル−Ｄ−グルコピラノシドの合成
糖構造を含有する化合物としてメチル ２，３，６−トリ−Ｏ−ベンジル−Ｄ−グルコピラノシドを用いて実施例２と同様の方法により、表題化合物を黄色油状物として得た（565 mg, 収率90％）。
¹H-NMR(270MHz, CDCl₃ ) δ:7.36-7.24(m,15H), 7.07(d,1H), 6.97(m,2H), 4.98(d,1H), 4.80-4.62(m,6H), 4.43(d,1H), 4.34(d,1H), 3.94(t,1H), 3.72-3.52(m,5H), 3.38(s,3H)
【００４３】
実験例１：保護基の脱離（メチル ２，３，４−トリ−Ｏ−ベンジル−Ｄ−グルコピラノシドの合成）
メチル ６−Ｏ−（４−アジド−３−クロロベンジル）−２，３，４−トリ−Ｏ−ベンジル−Ｄ−グルコピラノシド(126 mg, 0.2 mmol)をテトラヒドロフラン（ＴＨＦ，1 ml）に溶解し、ＰＰｈ₃ (63 mg, 0.24 mmol) を加えて、室温で１時間撹拌した。続いて反応溶液に水(10 μl)、氷酢酸(10 ml) 及びＤＤＱ(68 mg, 0.3 mmol) を加え、さらに1.5 時間撹拌した。反応溶液を酢酸エチルで希釈し、５％アスコルビン酸水溶液、飽和重曹水、飽和食塩水で洗浄した。無水硫酸ナトリウムで乾燥後、減圧下に溶媒を除去し、褐色の油状物を得た。シリカゲルカラムクロマトグラフィー（溶離液；ジクロロメタン：酢酸エチル＝40:1）で精製することにより、表題化合物を無色油状物として得た(86 mg, 収率92％) 。
¹H-NMR(270MHz, CDCl₃ ) δ:7.37-7.24(m,15H), 4.99(d,1H), 4.90-4.77(m,3H), 4.65(dd,2H), 4.58(d,1H), 4.00(t,1H), 3.76-3.62(m,3H), 3.55-3.47(m,2H), 3.36(s,3H), 1.63(t,1H)
上記酢酸の代わりにシリカゲルを添加することによっても同様な結果が得られた。
【００４４】
実験例２：耐酸性試験
メチル ６−Ｏ−（４−アジド−３−クロロベンジル）−２，３，４−トリ−Ｏ−ベンジル−Ｄ−グルコピラノシド（実施例２の化合物）を、塩化メチレン中、室温で２当量の三フッ化ホウ素−ジエチルエーテルにさらしたが、分解されなかった。
水酸基の保護基として４−メトキシベンジル基を有する〔２−（４−メトキシベンジルオキシ）エチル〕ベンゼン、また水酸基の保護基として４−アジドベンジル基を有するメチル ６−Ｏ−（４−アジドベンジル）−２，３，４−トリ−Ｏ−ベンジル−Ｄ−グルコピラノシドを用い、同様の実験を行った。その結果、〔２−（４−メトキシベンジルオキシ）エチル〕ベンゼンは速やかに分解し、メチル ６−Ｏ−（４−アジドベンジル）−２，３，４−トリ−Ｏ−ベンジル−Ｄ−グルコピラノシドは６時間で約２５％分解した。
以上のことから、従来の水酸基の保護基とは異なり、本発明によるアジドハロゲノベンジル基は酸に対して優れた安定性を示すことがわかる。
【００４５】
実験例３：選択的脱離試験
（１）アジドクロロベンジル基及びメトキシベンジル基で保護されたエチレングリコールの合成：１−アジド−２−クロロ−４−（４−メトキシベンジルオキシエトキシメチル）ベンゼンの合成
２−（４−メトキシベンジルオキシ）エタノール(500 mg, 2.75 mmol) をＤＭＦ(10 ml) に溶解し、０℃で水素化ナトリウム(60%油中，132 mg, 3.30 mmol)を加え、30分間撹拌した。続いて、４−アジド−３−クロロベンジルブロマイド(813 mg, 3.30 mmol) を少しずつ加えた。反応液を０℃で30分間、室温で２時間撹拌した後、氷水を加え、エーテルで抽出した。エーテル層を水、次いで飽和食塩水で洗浄し、無水硫酸ナトリウムで乾燥した。減圧下で溶媒を除去し、得られた残渣をシリカゲルカラムクロマトグラフィー（溶離液；ヘキサン：酢酸エチル＝10:1）で精製することにより、表題化合物を黄色油状物として得た(805 mg,収率84％）。
¹H-NMR(270MHz, CDCl₃ ) δ:7.39(d,1H), 7.30-7.24(m,3H), 7.13(d,1H), 6.90-6.85(m,2H), 4.51(s,4H), 3.80(s,3H), 3.64(s,4H)
【００４６】
（２）アジドクロロベンジル基の脱離：２−（４−メトキシベンジルオキシ）エタノールの合成
上記（１）で得られた１−アジド−２−クロロ−４−（４−メトキシベンジルオキシエトキシメチル）ベンゼン(174 mg, 0.5 mmol)をＴＨＦ(1 ml)に溶解し、ＰＰｈ₃ (157 mg, 0.6 mmol) を加え、室温で１時間撹拌した。続いて反応溶液に水(10 ml) 、氷酢酸(10 ml) 及びＤＤＱ(159 mg, 0.7 mmol)を加え、さらに室温で１時間撹拌した。反応溶液を酢酸エチルで希釈し、５％アスコルビン酸水溶液、飽和重曹水、飽和食塩水で洗浄した。無水硫酸ナトリウムで乾燥後、減圧下に溶媒を除去し、得られた褐色の油状物をシリカゲルカラムクロマトグラフィー（溶離液；ジクロロメタン：酢酸エチル＝２：１）で精製することにより、表題化合物を黄色油状物として得た(68 mg, 収率75％）。
¹H-NMR(270MHz, CDCl₃ ) δ:7.27(m,2H), 6.89(m,2H), 4.49(s,2H), 3.81(s,3H), 3.74(m,2H), 3.57(m,2H)
【００４７】
（３）メトキシベンジル基の脱離：２−（４−アジド−３−クロロベンジルオキシ）エタノールの合成
上記（１）で得られた１−アジド−２−クロロ−４−（４−メトキシベンジルオキシエトキシメチル）ベンゼン(348 mg, 1 mmol)をＴＨＦ(2 ml)に溶解し、水(0.1 ml)とＤＤＱ(34 mg, 1.50 mmol)を加え、室温で７時間撹拌した。反応溶液を酢酸エチルで希釈し、５％アスコルビン酸水溶液、飽和重曹水、飽和食塩水で洗浄し、無水硫酸ナトリウムで乾燥した。減圧下に溶媒を除去し、得られた褐色の油状物をシリカゲルカラムクロマトグラフィー（溶離液；ヘキサン：酢酸エチル＝２：１）で精製することにより、表題化合物を黄色油状物として得た(201 mg,収率88％）。
¹H-NMR(270MHz, CDCl₃ ) δ:7.38(d,1H), 7.26(m,1H), 7.15(d,1H), 4.51(s,2H), 3.78(t,2H), 3.60(t,2H)
【００４８】
以上のように、本発明によるアジドハロゲノベンジル基は、従来のメトキシベンジル基と異なる条件下で脱保護できる。即ち、ＤＤＱと水のみではアジドハロゲノベンジル基は脱保護されないが、メトキシベンジル基は脱保護され、一方、ＰＰｈ₃ 、ＤＤＱ、水及び酢酸ではアジドハロゲノベンジル基は脱保護されるが、メトキシベンジル基は脱保護されない。かくして、本発明によるアジドハロゲノベンジル基を、従来の保護基と共に使用することにより、保護基の選択的脱離を行うことができる。
【００４９】
以下の実施例４〜９は、本発明の保護基を用いる固相合成法による糖鎖の合成例である。なお、反応式中の略号の意味は次のとおりである。
Ｂｚｌ：ベンジル
Ｐｈ：フェニル
Ｔｒｔ：トリフェニルメチル
ＭＰＭ：４−メトキシベンジル
Ｂｚ：ベンゾイル
Ｔｃｅ：２，２，２−トリクロロエチル
Ｔｒｏｃ：２，２，２−トリクロロエチルオキシカルボニル
Ｅｔ：エチル
Ｂｕ：ブチル
Ｔｆ：トリフルオロメチルスルホニル
Ａｃ：アセチル
【００５０】
実施例４：フェニル ６−Ｏ−（４−アジド−３−クロロベンジル）−２，３，４−トリ−Ｏ−ベンジル−１−チオ−Ｄ−グルコピラノシド（４）の合成
【００５１】
【化１０】

【００５２】
（ａ）１，６−アンヒドロ−２，３，４−トリ−Ｏ−ベンジル−β−Ｄ−グルコピラノシド（２）の合成
水素化ナトリウム(60%油中, 13.2 g, 0.33 mol) を無水エーテルで洗浄し、ＤＭＦ(100 ml)に懸濁させた。ここに１，６−アンヒドロ−β−Ｄ−グルコピラノシド（１）(16.2 g, 0.1 mol) を加え室温で30分間攪拌した。次いで、０℃に冷却し、臭化ベンジル(39.3 ml, 0.33 mol) を滴下し、そのまま室温で２時間攪拌した。水(200 ml)を加え、酢酸エチルで３回抽出し、有機層を合わせ、飽和食塩水で洗浄し、無水硫酸ナトリウムで乾燥した。減圧下に溶媒を除去し、白色結晶を得た。熱メタノールから再結晶し白色結晶の１，６−アンヒドロ−２，３，４−トリ−Ｏ−ベンジル−β−Ｄ−グルコピラノシド（２）を得た(38.2 g,収率88%)。
【００５３】
（ｂ）フェニル ２，３，４−トリ−Ｏ−ベンジル−１−チオ−Ｄ−グルコピラノシド（３）の合成
１，６−アンヒドロ−２，３，４−トリ−Ｏ−ベンジル−β−Ｄ−グルコピラノシド（２）(15.0 g, 34.7 mmol) とフェニルチオトリメチルシラン(19.7 ml, 104 mmol) のジクロロメタン溶液(100 ml)にヨウ化亜鉛(11.1 g, 34.7 mmol) を加え室温で４時間攪拌した。反応溶液を濾過し、濾液を減圧下に濃縮した。残渣をメタノール(100 ml)に溶かし、１Ｎ塩酸(50 ml) を加え、室温で15分間攪拌した。減圧下にメタノールを除去した後、酢酸エチルで抽出し、有機層を飽和炭酸水素ナトリウム水溶液、次いで飽和食塩水で洗浄した。無水硫酸ナトリウムで乾燥後、減圧下に溶媒を除去して得た油状物をヘキサン中で結晶化させ、白色結晶のフェニル ２，３，４−トリ−Ｏ−ベンジル−１−チオ−Ｄ−グルコピラノシド（３）を得た(19.5 g,収率89%)。
【００５４】
（ｃ）フェニル ６−Ｏ−（４−アジド−３−クロロベンジル）−２，３，４−トリ−Ｏ−ベンジル−１−チオ−Ｄ−グルコピラノシド（４）の合成
フェニル ２，３，４−トリ−Ｏ−ベンジル−１−チオ−Ｄ−グルコピラノシド（３）(1.09 g, 2.00 mmol) のＤＭＦ(10 ml) 溶液に水素化ナトリウム(60%油中, 96 mg, 2.40 mmol) を加え、室温で15分間攪拌した。０℃に冷却し、４−アジド−３−クロロベンジルブロミド(592 mg, 2.40 mmol) を加え、そのまま室温で４時間攪拌した。水(30 ml) を加え、酢酸エチルで２回抽出し、有機層を合わせ、飽和食塩水で洗浄し、無水硫酸ナトリウムで乾燥した。減圧下に溶媒を除去し、得られた残渣をシリカゲルカラムクロマトグラフィー（溶離液；ヘキサン：酢酸エチル＝５：１）で精製し、微黄色結晶のフェニル ６−Ｏ−（４−アジド−３−クロロベンジル）−２，３，４−トリ−Ｏ−ベンジル−１−チオ−Ｄ−グルコピラノシド（４）を得た(1.33 g,収率94%)。
【００５５】
実施例５：フェニル ６−Ｏ−（４−アジド−３−クロロベンジル）−２，３，４−トリ−Ｏ−ベンゾイル−１−チオ−β−Ｄ−グルコピラノシド（１１）の合成
【００５６】
【化１１】

【００５７】
【化１２】

【００５８】
（ａ）フェニル ６−Ｏ−トリフェニルメチル−１−チオ−β−Ｄ−グルコピラノシド（６）の合成
フェニル １−チオ−β−Ｄ−グルコピラノシド（５）(7.01 g, 25.8 mmol) 、トリフェニルメチルクロリド(9.33 g, 33.5 mmol) をピリジン(20 ml) に懸濁し、５時間還流した。溶媒を減圧下に除去した後、残渣を酢酸エチルに溶かし、水、次いで飽和食塩水で洗浄し、無水硫酸ナトリウムで乾燥した。減圧下に溶媒を除去し得られた残渣をシリカゲルカラムクロマトグラフィー（溶離液；ジクロロメタン：酢酸エチル＝１：１）で精製し、白色固体のフェニル ６−Ｏ−トリフェニルメチル−１−チオ−β−Ｄ−グルコピラノシド（６）を得た(13.1 g,収率99%)。
【００５９】
（ｂ）フェニル ２，３，４−トリ−Ｏ−（４−メトキシベンジル）−６−Ｏ−トリフェニルメチル−１−チオ−β−Ｄ−グルコピラノシド（７）の合成
フェニル ６−Ｏ−トリフェニルメチル−１−チオ−β−Ｄ−グルコピラノシド（６）(13.0 g, 25.3 mmol) のＤＭＦ(80 ml) 溶液に水素化ナトリウム(60%油中, 3.22 g, 80.5 mmol)を加え、室温で20分間攪拌した。０℃に冷却し、４−メトキシベンジルクロリド(12.6 g, 80.5 mmol) を加え、そのまま室温で一晩攪拌した。冷水を加え、エーテルで２回抽出し、合わせたエーテル層を水、次いで飽和食塩水で洗浄した。無水硫酸ナトリウムで乾燥後、減圧下に溶媒を除去して得た残渣をシリカゲルカラムクロマトグラフィー（溶離液；ヘキサン：酢酸エチル＝３：１）で精製し、白色油状物のフェニル ２，３，４−トリ−Ｏ−（４−メトキシベンジル）−６−Ｏ−トリフェニルメチル−１−チオ−β−Ｄ−グルコピラノシド（７）を得た(18.8 g,収率85%)。
【００６０】
（ｃ）フェニル ２，３，４−トリ−Ｏ−（４−メトキシベンジル）−１−チオ−β−Ｄ−グルコピラノシド（８）の合成
フェニル ２，３，４−トリ−Ｏ−（４−メトキシベンジル）−６−Ｏ−トリフェニルメチル−１−チオ−β−Ｄ−グルコピラノシド（７）(3.44 g, 3.93 mmol) のエーテル(8 ml)溶液に、ギ酸(8 ml)を加え、室温で５時間攪拌した。反応溶液を、水、飽和炭酸水素ナトリウム水溶液、飽和食塩水の順で洗浄した後、減圧下に溶媒を除去した。残渣をエタノール(5 ml)と１Ｎ水酸化ナトリウム水溶液(5 ml)の混液に懸濁し、室温で一晩攪拌した。減圧下にエタノールを留去した後、エーテルで２回抽出した。合わせたエーテル層を飽和食塩水で洗浄した後、無水硫酸ナトリウムで乾燥した。減圧下に溶媒を除去し、残渣をシリカゲルカラムクロマトグラフィー（溶離液；ヘキサン：酢酸エチル＝２：１→１：１）で精製し、白色結晶のフェニル ２，３，４−トリ−Ｏ−（４−メトキシベンジル）−１−チオ−β−Ｄ−グルコピラノシド（８）を得た(1.28 g,収率51%)。
【００６１】
（ｄ）フェニル ６−Ｏ−（４−アジド−３−クロロベンジル）−２，３，４−トリ−Ｏ−（４−メトキシベンジル）−１−チオ−β−Ｄ−グルコピラノシド（９）の合成
フェニル ２，３，４−トリ−Ｏ−（４−メトキシベンジル）−１−チオ−β−Ｄ−グルコピラノシド（８）(1.25 g, 1.98 mmol) 、４−アジド−３−クロロベンジルブロミド(584 mg, 2.37 mmol) のＤＭＦ(10 ml) 溶液に、水素化ナトリウム(60%油中, 95 mg, 2.37 mmol) を加え、室温で３時間攪拌した。冷水を加え、エーテルで２回抽出し、合わせたエーテル層を水、次いで飽和食塩水で洗浄した後、無水硫酸ナトリウムで乾燥した。減圧下に溶媒を除去して得られた残渣をシリカゲルカラムクロマトグラフィー（溶離液；ヘキサン：酢酸エチル＝４：１）で精製し、白色結晶のフェニル ６−Ｏ−（４−アジド−３−クロロベンジル）−２，３，４−トリ−Ｏ−（４−メトキシベンジル）−１−チオ−β−Ｄ−グルコピラノシド（９）を得た(1.25 g,収率79%)。
【００６２】
（ｅ）フェニル ６−Ｏ−（４−アジド−３−クロロベンジル）−１−チオ−β−Ｄ−グルコピラノシド（１０）の合成
フェニル ６−Ｏ−（４−アジド−３−クロロベンジル）−２，３，４−トリ−Ｏ−（４−メトキシベンジル）−１−チオ−β−Ｄ−グルコピラノシド（９）(1.24 g, 1.55 mmol) のジクロロメタン(10 ml) 溶液に、水(0.5 ml)、ＤＤＱ(1.41 g, 6.21 mmol) を加え、室温で３時間攪拌した。５％ Ｌ−アスコルビン酸水溶液を加え、しばらく攪拌した後、酢酸エチルで抽出した。有機層を飽和炭酸水素ナトリウム水溶液、次いで飽和食塩水で洗浄した後、無水硫酸ナトリウムで乾燥した。減圧下に溶媒を除去して得られた残渣をシリカゲルカラムクロマトグラフィー（溶離液；ジクロロメタン：酢酸エチル＝１：３）で精製し、黄色結晶のフェニル ６−Ｏ−（４−アジド−３−クロロベンジル）−１−チオ−β−Ｄ−グルコピラノシド（１０）を得た(584 mg,収率86%)。
【００６３】
（ｆ）フェニル ６−Ｏ−（４−アジド−３−クロロベンジル）−２，３，４−トリ−Ｏ−ベンゾイル−１−チオ−β−Ｄ−グルコピラノシド（１１）の合成
フェニル ６−Ｏ−（４−アジド−３−クロロベンジル）−１−チオ−β−Ｄ−グルコピラノシド（１０）(580 mg, 1.32 mmol) のピリジン(5 ml)溶液に、０℃で、塩化ベンゾイル(609μl, 5.28 mmol) を加え、そのまま室温で２時間攪拌した。水を加え、酢酸エチルで抽出し、有機層を飽和食塩水で洗浄した後、無水硫酸ナトリウムで乾燥した。減圧下に溶媒を除去して微黄色結晶のフェニル ６−Ｏ−（４−アジド−３−クロロベンジル）−２，３，４−トリ−Ｏ−ベンゾイル−１−チオ−β−Ｄ−グルコピラノシド（１１）を得た(934 mg,収率94%)。
【００６４】
実施例６：式（１７）の２，３，４−トリ−Ｏ−ベンジル−グルコピラノシドが固定化されたポリスチレン樹脂誘導体の合成
【００６５】
【化１３】

【００６６】
【化１４】

【００６７】
（ａ）４−ブロモメチルフェニル酢酸 ２，２，２−トリクロロエチルエステル（１３）の合成
４−ブロモメチルフェニル酢酸（１２）(10.3 g, 44.8 mmol) をジクロロメタン(30 ml) に懸濁させ、０℃でトリフルオロ酢酸無水物(9.28 ml, 67.2 mmol)を加え30分間攪拌した。次いで、２，２，２−トリクロロエタノール(6.47 ml, 67.2 mmol)を滴下し、そのまま室温で一晩攪拌した。水、飽和炭酸水素ナトリウム水溶液、飽和食塩水で洗浄した後、無水硫酸ナトリウムで乾燥し、減圧下に溶媒を除去し無色油状物を得た。この油状物を一晩放置することにより白色結晶の４−ブロモメチルフェニル酢酸 ２，２，２−トリクロロエチルエステル（１３）を得た(15.9 g,収率98%)。
【００６８】
（ｂ）４−（４−ヒドロキシメチルフェニルアセトキシメチル）フェニル酢酸 ２，２，２−トリクロロエチルエステル（１４）の合成
炭酸セシウム(1.63 g, 5.00 mmol) の水(50 ml) 溶液に、４−ブロモメチルフェニル酢酸（１２）(1.15 g, 5.00 mmol) を加え、１時間還流した。冷却後、減圧下に濃縮乾固させ、得られた残渣を、ＤＭＦ(10 ml) に懸濁させた。ここに、４−ブロモメチルフェニル酢酸 ２，２，２−トリクロロエチルエステル（１３）(1.80 g, 5.00 mmol) を加え室温で一晩攪拌した。水を加え、酢酸エチルで抽出し、有機層を飽和食塩水で洗浄した。無水硫酸ナトリウムで乾燥後、減圧下に溶媒を除去して得た油状物をシリカゲルカラムクロマトグラフィー（溶離液；ジクロロメタン：酢酸エチル＝１５：１）で精製し、白色固体の４−（４−ヒドロキシメチルフェニルアセトキシメチル）フェニル酢酸 ２，２，２−トリクロロエチルエステル（１４）を得た(994 mg,収率45%)。
【００６９】
（ｃ）式（１５）の２，２，２−トリクロロエチルエステル誘導体の合成
４−（４−ヒドロキシメチルフェニルアセトキシメチル）フェニル酢酸 ２，２，２−トリクロロエチルエステル（１４）(1.94 g, 4.35 mmol) 、フェニル ２，３，４−トリ−Ｏ−ベンジル−６−Ｏ−（２，２，２−トリクロロエチルオキシカルボニル）−１−チオ−Ｄ−グルコピラノシド(2.94 g, 3.95 mmol) 、ヨードソベンゼン(956 mg, 4.35 mmol) 、過塩素酸銀(328 mg, 1.58 mmol) 、モレキュラーシーブ（登録商標）４Ａ（約 1 g) をエーテル(15 ml) に懸濁させ、窒素雰囲気下に室温で30分間攪拌した。０℃に冷却し、トリメチルシリルクロリド(101μl, 0.79 mmol) を加え30分間攪拌した。反応溶液を濾過し、濾液を飽和炭酸水素ナトリウム水溶液、次いで飽和食塩水で洗浄した後、無水硫酸ナトリウムで乾燥した。減圧下に溶媒を除去し得られた残渣をシリカゲルカラムクロマトグラフィー（溶離液；ヘキサン：酢酸エチル＝４：１）で精製し、式（１５）の２，２，２−トリクロロエチルエステル誘導体を無色油状物として得た(3.22 g,収率77%)。α−アノマー／β−アノマー＝９５／５
【００７０】
（ｄ）式（１６）のカルボン酸誘導体の合成
式（１５）の２，２，２−トリクロロエチルエステル誘導体(3.22 g, 3.06 mmol) を90％酢酸に溶かし、粉末状亜鉛(4.00 g, 61.1 mmol) を加え、室温で２時間攪拌した。反応溶液を濾過し、濾液を酢酸エチルで希釈し、飽和食塩水で洗浄した後、無水硫酸ナトリウムで乾燥した。減圧下に溶媒を除去し得られた残渣をシリカゲルカラムクロマトグラフィー（溶離液；ジクロロメタン：メタノール＝９７：３）で精製し、式（１６）のカルボン酸誘導体を白色固体として得た(2.11 g,収率93%)。
【００７１】
（ｅ）式（１７）のポリスチレン樹脂誘導体の合成
式（１６）のカルボン酸誘導体(896 mg, 1.20 mmol) 、アミノメチル化ポリスチレン樹脂(0.83 mmol/g, 1.20 g, 1 mmol) 、ジイソプロピルカルボジイミド（ＤＩＣ）(219μl, 1.40 mmol) 、１−ヒドロキシベンゾトリアゾール（ＨＯＢｔ）(189 mg, 1.40 mmol) 及びトリエチルアミン(195μl, 1.40 mmol) をジクロロメタン(10 ml) に懸濁させ、室温で２時間振り混ぜた。樹脂を濾取し、ＤＭＦ、ジクロロメタンで洗浄した後、減圧下に乾燥させ、式（１７）のポリスチレン樹脂誘導体を得た(1.88 g,収率約100%) 。
【００７２】
実施例７：式（１７）のポリスチレン樹脂誘導体と、式（４）又は式（１１）の４−アジド−３−クロロベンジル化チオグリコシドとのグリコシル化反応
【００７３】
【化１５】

【００７４】
実施例４又は実施例５で得られた式（４）（Ｒ＝ベンジル）又は式（１１）（Ｒ＝ベンゾイル）のチオグリコシド(75 mmol) 、実施例６で得られた式（１７）のポリスチレン樹脂誘導体(25 mmol) 、テトラブチルアンモニウム塩(25 mmol)(Ｒ＝ベンジルのときは過塩素酸テトラブチルアンモニウムを用い、Ｒ＝ベンゾイルのときはトリフルオロメタンスルホン酸テトラブチルアンモニウムを用いた）及びモレキュラーシーブ（登録商標）４Ａをジクロロメタン(1 ml)に懸濁させ、15分間振り混ぜた。ここに、Ｎ−ブロモスクシンイミド(15 mg, 83 mmol)を加え、室温で一晩振り混ぜた。モレキュラーシーブ（登録商標）４Ａを取り除き、樹脂を濾取し、ジクロロメタンで洗浄した後、減圧下に乾燥し、式（１８）のポリスチレン樹脂誘導体を得た。４−アジド−３−クロロベンジル化グリコシドの樹脂への導入率は３０〜７５％であった。導入率が低い場合は、反応を２〜３回繰り返せばよい。
【００７５】
実施例８：式（１８）のポリスチレン樹脂誘導体からの４−アジド−３−クロロベンジル基の除去
【００７６】
【化１６】

【００７７】
４−アジド−３−クロロベンジル基で保護された水酸基を含有する式（１８）のポリスチレン樹脂誘導体 (約70 mg, 10 〜15μmol の４−アジド−３−クロロベンジル基が存在する）及びＰＰｈ₃ (20 mg, 75μmol)をＴＨＦ(1 ml)に加えて室温で1.5 時間振り混ぜた。樹脂を濾取した後、ＴＨＦで洗浄し、再度この樹脂をＴＨＦ(1 ml)に加えた。ここに、ＤＤＱ(8.5 mg, 37.5 μmol)及び50％酢酸水溶液(20 μl)を加え、室温で３時間振り混ぜた。樹脂を濾取した後、ＤＭＦ、次いでジクロロメタンで洗浄し、減圧下に樹脂を乾燥させ、定量的に式（１９）のポリスチレン樹脂誘導体を得た。
【００７８】
実施例９：式（１９）のポリスチレン樹脂誘導体と、式（４）又は式（１１）の４−アジド−３−クロロベンジル化チオグリコシドとのグリコシル化反応
【００７９】
【化１７】

【００８０】
式（４）（Ｒ＝ベンジル）又は式（１１）（Ｒ＝ベンゾイル）のチオグリコシド(75 mmol) 、式（１９）のポリスチレン樹脂誘導体(8 mmol)、テトラブチルアンモニウム塩(25 mmol)(Ｒ＝ベンジルのときは過塩素酸テトラブチルアンモニウムを用い、Ｒ＝ベンゾイルのときはトリフルオロメタンスルホン酸テトラブチルアンモニウムを用いた）及びモレキュラーシーブ（登録商標）４Ａをジクロロメタン(1 ml)に懸濁させ、15分間振り混ぜた。ここに、Ｎ−ブロモスクシンイミド(15 mg, 83 mmol)を加え、室温で一晩振り混ぜた。モレキュラーシーブ（登録商標）４Ａを取り除き、樹脂を濾取し、ジクロロメタンで洗浄した後、減圧下に乾燥し、式（２０）のポリスチレン樹脂誘導体を得た。４−アジド−３−クロロベンジル化グリコシドの樹脂への導入率は３３％であった。
【００８１】
【発明の効果】
以上のように、ベンジル基にアジド基を配することによって、必要な際には還元してアミノ基へ変換することにより穏和な条件下で容易に保護基を除去することができ、ベンジル基に配したハロゲノ基によって、耐酸性が向上する。従って、本発明によるアジドハロゲノベンジル基は、特に糖鎖の伸長のために連続して酸性環境下に置かれるような固相合成においても、安定な水酸基の保護基として有用である。また本発明によれば、このようなアジドハロゲノベンジル基を導入し得るアジドハロゲノベンジル誘導体、該誘導体を用いて保護された糖化合物及び該誘導体を用いた水酸基の保護方法が提供できる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to various compounds having a hydroxyl group, particularly a novel azidohalogenobenzyl derivative useful for protecting hydroxyl groups of sugars and sugar derivatives, and more particularly, protection of hydroxyl groups which are excellent in acid resistance and can be deprotected under mild conditions. The present invention relates to a novel azidohalogenobenzyl derivative into which a group can be introduced. The present invention also relates to a sugar compound protected using the derivative, and a method for protecting a hydroxyl group using the derivative.
[0002]
[Prior art / problems to be solved by the invention]
In reactions using hydroxyl group-containing compounds, particularly in the synthesis of sugar chains, the sugars and derivatives thereof used have many other hydroxyl groups that are not involved in the desired bond formation, so these hydroxyl groups are protected with protecting groups, It is necessary to exclude it from the sugar chain elongation reaction system. On the other hand, a protective group for a specific hydroxyl group involved in sugar chain bonding must be sequentially removed to function as an acceptor. That is, for example, in a sugar chain elongation synthesis, a specific protecting group is bonded to a specific hydroxyl group in advance so that it can be cleaved when necessary, and selective cleavage and bonding with a new sugar to be added are repeated. These protecting groups are essential to be stable under various conditions such as glycosidic bond forming reactions and other protecting group cleavage reactions, in addition to the property that they can be selectively removed as required. Among them, Lewis acids and the like are used for glycosidation, and especially in automatic synthesis such as solid-phase synthesis method, since it is continuously placed in an acidic environment, it is necessary that the protecting group used has excellent acid resistance. Become.
In particular, in the automatic synthesis of sugar chains, the removal of the protecting group must be carried out under relatively mild conditions such as temperature and pH.
Conventional protective groups for hydroxyl groups such as p-methoxybenzyl group and p-azidobenzyl group can be removed under relatively mild conditions, so there is no problem in this respect, but the acid resistance is poor. Therefore, it has been extremely difficult to efficiently perform the synthesis of sugar chains using these protecting groups, particularly the synthesis of sugar chains having side chains.
In view of the above situation, hydroxyl protecting groups have been developed, but sufficient hydroxyl protecting groups that are excellent in acid resistance and can be removed under mild conditions have not yet been obtained. Absent.
[0003]
The present invention not only protects ordinary hydroxyl groups but also can be applied not only to conventional sugar chain synthesis in the liquid phase, but also to continuous sugar chain solid phase synthesis using an automatic synthesizer. It aims at providing the novel derivative which can introduce | transduce into a hydroxyl-containing compound. Another object of the present invention is to provide a sugar compound protected by using the derivative and a method for protecting a hydroxyl group using the derivative.
[0004]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventors have found that a hydroxyl-protecting group obtained by using an azidohalogenobenzyl derivative represented by the following general formula (I) has excellent acid resistance, The present invention has been completed by finding that it can be rapidly detached under mild conditions and can be applied to a solid-phase synthesis method of continuous sugar chains using an automatic synthesizer.
[0005]
That is, the present invention is as follows.
(1) General formula (I)
[0006]
[Chemical 7]

[0007]
(Wherein A represents a halogen atom, B represents a halogen atom or a hydrogen atom, and X represents a group capable of reacting with a hydroxyl group) [hereinafter referred to as an azidohalogenobenzyl derivative (I)] ].
[0008]
(2) The azidohalogenobenzyl derivative according to (1), wherein in general formula (I), X represents a halogen atom or imidoyloxy group.
[0009]
(3) The azidohalogenobenzyl derivative according to (1), wherein in general formula (I), B represents a hydrogen atom and X represents a halogen atom.
[0010]
(4) The azidohalogenobenzyl derivative according to (1), which is 4-azido-3-chlorobenzyl bromide.
[0011]
(5) The hydrogen atom of at least one hydroxyl group has the general formula (II)
[0012]
[Chemical 8]

[0013]
(Wherein each symbol is as defined above), a sugar compound substituted with an azidohalogenobenzyl group [hereinafter referred to as azidohalogenobenzyl group (II)].
[0014]
(6) The sugar compound according to (5), which is obtained by reacting a monosaccharide, oligosaccharide or polysaccharide with an azidohalogenobenzyl derivative (I).
[0015]
(7) A method for protecting a hydroxyl group, comprising reacting the azidohalogenobenzyl derivative (I) with a hydroxyl group-containing compound to replace a hydrogen atom of the hydroxyl group of the hydroxyl group-containing compound with an azidohalogenobenzyl group (II).
[0016]
(8) The protection method according to (7), wherein the hydroxyl group-containing compound is a compound containing a sugar structure.
[0017]
(9) A reagent for protecting a hydroxyl group, containing the azidohalogenobenzyl derivative (I).
[0018]
(10) The reagent according to (9), wherein in general formula (I), X represents a halogen atom or an imidoyloxy group.
[0019]
(11) The reagent according to (9), wherein in general formula (I), B represents a hydrogen atom and X represents a halogen atom.
[0020]
(12) The reagent according to (9), wherein the azidohalogenobenzyl derivative (I) is 4-azido-3-chlorobenzyl bromide.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the definition of each substituent is as follows.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a chlorine atom and a bromine atom are preferable. More preferably, it is a chlorine atom.
The group capable of reacting with a hydroxyl group is a group capable of reacting with a hydroxyl group and leaving together with a hydrogen atom of the hydroxyl group, and examples thereof include a halogen atom and an imidoyloxy group as described above. A halogen atom is preferred.
Here, the imidoyloxy group is an imidoyloxy group having an alkyl group having 1 to 5 carbon atoms, and may further have a halogen atom or the like as a substituent. Specific examples include 1,1,1-trichloroethaneimidoyloxy group.
[0022]
The azidohalogenobenzyl derivative (I) of the present invention is preferably 4-azido-3-chlorobenzyl bromide.
[0023]
The azidohalogenobenzyl derivative (I) of the present invention can be synthesized as follows, for example, when X is a halogen atom.
[0024]
[Chemical 9]

[0025]
(Where X ¹ Represents a halogen atom, and A and B are as defined above)
That is, the aminohalogenotoluene represented by the general formula (III) [hereinafter referred to as aminohalogenotoluene (III)] is treated with sodium nitrite in an aqueous hydrochloric acid solution and then with sodium azide to give the general formula (IV ) (Hereinafter referred to as azidohalogenotoluene (IV)) [New Experimental Chemistry Course XVI Synthesis and Reaction of Organic Compounds III, Maruzen, 1665-1666 (1978)]. Further, for example, in the presence of a catalyst such as 2,2′-azobisisobutyronitrile (AIBN), N-halogenosuccinimide and By reaction, the azidohalogenobenzyl derivative (I) of the present invention can be obtained [New Experimental Chemistry Course XVI. Synthesis and Reaction of Organic Compounds I, Maruzen, pp. 336-339 (1979)].
Further, instead of N-halogenosuccinimide, halogen gas such as chlorine gas or bromine gas, or solid or liquid halogen such as solid iodine or liquid bromine may be used.
[0026]
The synthesis of azidohalogenotoluene (IV) is usually carried out by adding 1 to 10 equivalents, preferably 1 to 5 equivalents, more preferably 1 to 2 equivalents of sodium nitrite with respect to aminohalogenotoluene (III), and -10 ° C. After stirring for several minutes to several tens of minutes at room temperature, 1 to 5 equivalents, preferably 1 to 2 equivalents of sodium azide is added to aminohalogenotoluene (III), and further, the temperature is further from -10 ° C to room temperature for several minutes. It is carried out by stirring for tens of minutes.
[0027]
As the aminohalogenotoluene (III) as a starting material, for example, 2-amino-4-fluorotoluene, 2-amino-5-fluorotoluene, 2-amino-6-fluorotoluene, 3-amino-4-fluorotoluene, 3-amino-5-fluorotoluene, 3-amino-6-fluorotoluene, 4-amino-2-fluorotoluene, 4-amino-3-fluorotoluene, 2-amino-3-chlorotoluene, 2-amino-5 -Chlorotoluene, 2-amino-6-chlorotoluene, 3-amino-4-chlorotoluene, 3-amino-6-chlorotoluene, 4-amino-2-chlorotoluene, 4-amino-3-chlorotoluene, 2 -Amino-5-bromotoluene, 2-amino-6-bromotoluene, 2-amino-5-iodotoluene, 4-amino- - Iodotoluene, 4-amino-2,6-dichlorotoluene, 2-amino-4,6-dichlorotoluene, 4-amino-2,5-dichlorotoluene, and the like.
[0028]
In the reaction of azidohalogenotoluene (IV) with N-halogenosuccinimide, usually 1 to 5 equivalents, preferably 1 to 2 equivalents of N-halogenosuccinimide is used with respect to azidohalogenotoluene (IV). Examples of the solvent used in the reaction include aromatic hydrocarbons such as benzene, toluene and xylene, and halogenated hydrocarbons such as dichloromethane and dichloroethane. These solvents are preferably used in an anhydrous state. The reaction temperature is usually the boiling point of the solvent used, and the reaction time is usually from several tens of minutes to several tens of hours.
[0029]
Examples of the N-halogenosuccinimide used include N-chlorosuccinimide, N-bromosuccinimide, N-iodosuccinimide and the like.
[0030]
When X is an imidoyloxy group, for example, a method in which a corresponding azidohalogenobenzyl alcohol is reacted with trichloroacetonitrile in a solvent such as dichloromethane in the presence of sodium hydride [4th edition Experimental Chemistry Course Organic Synthesis VIII, Maruzen, pp. 274-275 (1990)] or the corresponding azidohalogenobenzyl alcohol in a solvent such as dichloromethane in the presence of cesium carbonate in the presence of chloroacetonitrile or the like, by a synthesis method known per se. A halogenobenzyl derivative (I) can be obtained.
[0031]
The obtained azidohalogenobenzyl derivative (I) of the present invention is useful for protecting the hydroxyl group of the hydroxyl group-containing compound.
The hydroxyl group-containing compound includes a compound containing a sugar structure.
By reacting a compound containing a sugar structure with the azidohalogenobenzyl derivative (I) of the present invention, a sugar compound in which the hydrogen atom of the hydroxyl group of the compound is substituted with the azidohalogenobenzyl group (II) is obtained.
[0032]
Specific examples of compounds containing a sugar structure include monosaccharides (glucose, arabinose, fucose, galactose, mannose, xylose, fructose, lyxose, allose, alinose, ribose, talose, gulose, idose, altrose, sorbitol, mannitol. , Glucosamine, etc.), oligosaccharides (maltose, isomaltose, turanose, gentiobiose, melibiose, planteobiose, primellellose, vicyanose, nigerose, laminaribiose, lutinose, cellobiose, xylobiose, maltotriose, gentianose, meletose, planteose Ketose, trehalose, sucrose, lactose, raffinose, xylotriose, etc.), polysaccharides (amylose, ficoll, dextst) , Starch, dextran, polydextrose, pullulan, cyclodextrin, glucomannoglycan, glucomannan, guar gum, gum arabic, glycosaminoglycan, etc.), complex carbohydrates (glycopeptides, glycoproteins, glycolipids, proteoglycans, etc.) Etc.
In addition, some of the hydroxyl groups of the compounds containing these sugar structures are acyl groups such as acetyl, acetylethylcarbonyl, and benzoyl, such as benzyl, nitrobenzyl, azidobenzyl, and methoxybenzyl. Those protected with a substituted alkyl group and the like are also included in the compound containing a sugar structure according to the present invention. Furthermore, the compound containing a sugar structure includes a compound containing a sugar structure bonded to, for example, a resin or a polymer via a linker.
[0033]
A sugar compound in which at least one hydroxyl group hydrogen atom is substituted with an azidohalogenobenzyl group (II) can be obtained by reacting a compound containing the above sugar structure with an azidohalogenobenzyl derivative (I).
The reaction is usually performed by stirring in a solvent such as N, N-dimethylformamide (DMF) at 0 ° C. to room temperature for several tens of minutes to several hours. At this time, for example, sodium hydride or the like is preferably used to activate the hydroxyl group.
[0034]
Examples of the sugar compound in which at least one hydroxyl group hydrogen atom is substituted with an azidohalogenobenzyl group (II) include methyl 6-O- (4-azido-3-chlorobenzyl) -2,3,4-tri -O-benzyl-D-glucopyranoside, methyl 4-O- (4-azido-3-chlorobenzyl) -2,3,6-tri-O-benzyl-D-glucopyranoside and the like.
[0035]
The method for protecting a hydroxyl group of the present invention is carried out by reacting an azidohalogenobenzyl derivative (I) with a hydroxyl group-containing compound and substituting the hydrogen atom of the hydroxyl group of the hydroxyl group-containing compound with an azidohalogenobenzyl group (II). .
Examples of the hydroxyl group-containing compound used in the present invention include a compound containing the sugar structure as described above, or a ring oxygen atom forming the sugar structure of the compound containing the sugar structure is a sulfur atom or CH. ₂ However, the hydroxyl group-containing compound is not limited to those described above, and any compound having a hydroxyl group may be used.
[0036]
The reaction between the azidohalogenobenzyl derivative (I) and the hydroxyl group-containing compound may be carried out according to the reaction between the azidohalogenobenzyl derivative (I) and a compound containing a sugar structure.
[0037]
The compound protected by the hydroxyl protecting group thus obtained, that is, by the azidohalogenobenzyl group (II), is described in, for example, Y.M. Deprotection can be easily performed under mild conditions by the method described in Oikawa et al., Tetrahedron Letter, 23, page 885 (1982). That is, triphenylphosphine (PPh _Three ) Is added to 1 to 5 equivalents, preferably 1 to 2 equivalents, with respect to the azidohalogenobenzyl group (II) and stirred, and water, acetic acid and 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) are added to the azide. By adding 1 to 5 equivalents, preferably 1 to 2 equivalents, and stirring with respect to the halogenobenzyl group (II), the protecting group can be easily removed. Silica gel may be used in place of acetic acid.
[0038]
【Example】
EXAMPLES Hereinafter, although a manufacture example, an experiment example, and an Example are given and this invention is demonstrated further in detail, this invention is not limited at all by these Examples.
[0039]
Production Example 1: Synthesis of 4-azido-3-chlorotoluene
4-Amino-3-chlorotoluene (14.16 g, 0.1 mol) was dissolved in a mixture of concentrated hydrochloric acid (50 ml), water (400 ml) and DMF (100 ml), and cooled with ice-saline solution. To this, an aqueous solution (50 ml) of sodium nitrite (6.9 g, 0.1 mol) was added dropwise at -5 ° C to 5 ° C over 20 minutes. Furthermore, after stirring for 10 minutes, the aqueous solution (50 ml) of sodium azide (6.5 g, 0.1 mol) was dripped over 20 minutes at 10 to 20 degreeC. The reaction solution was further stirred for 1.5 hours and then extracted with diethyl ether (150 ml × 3). The ether layers were combined, washed with saturated aqueous sodium hydrogen carbonate and saturated brine, and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure to give 17.14 g of the title compound as a brown oil.
MS (EI): M ⁺ = 167, 169
¹ H-NMR (270MHz, CDCl _Three ) δ: 7.19 (d, 1H), 7.06 (m, 2H), 2.31 (s, 3H)
[0040]
Example 1: Synthesis of 4-azido-3-chlorobenzyl bromide
4-Azido-3-chlorotoluene (17.14 g, 0.1 mol) is dissolved in anhydrous benzene (80 ml), N-bromosuccinimide (19.6 g, 0.11 mol) and AIBN (1.64 g, 0.01 mol) are added, and light-shielded. Under reflux in a nitrogen stream for 10 hours. Water (100 ml) was added and filtered. The aqueous layer of the filtrate was taken and extracted with ether. The organic layers were combined, washed with brine, and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure, and the resulting brown oil was purified by silica gel column chromatography (eluent: hexane) to give the title compound (14.2 g, yield 58%).
Melting point: 75-77 ° C
¹ H-NMR (270MHz, CDCl _Three ) δ: 7.42 (d, 1H), 7.31 (dd, 1H), 7.14 (d, 1H), 4,42 (s, 2H)
[0041]
Example 2: Synthesis of methyl 6-O- (4-azido-3-chlorobenzyl) -2,3,4-tri-O-benzyl-D-glucopyranoside
Methyl 2,3,4-tri-O-benzyl-D-glucopyranoside (1.16 g, 2.5 mmol) was dissolved in DMF (10 ml) and sodium hydride (60% in oil, 120 mg, 3.00 mmol) at 0 ° C. ) Was added and stirred for 15 minutes. Subsequently, 4-azido-3-chlorobenzyl bromide (740 mg, 3.00 mmol) was added in portions. After stirring at 0 ° C. for 30 minutes and at room temperature for 3 hours, ice water was added to the reaction solution, and the mixture was extracted with ethyl acetate. The solvent was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (eluent; hexane: ethyl acetate = 4: 1) to give the title compound as a yellow oil (1.48 g, yield). 94%).
¹ H-NMR (270MHz, CDCl _Three ) δ: 7.37-7.03 (m, 18H), 5.00-4.35 (m, 9H), 3.98 (t, 1H), 3.76-3.52 (m, 5H), 3.38 (s, 3H)
[0042]
Example 3: Synthesis of methyl 4-O- (4-azido-3-chlorobenzyl) -2,3,6-tri-O-benzyl-D-glucopyranoside
The title compound was obtained as a yellow oil (565 mg, yield) by the same method as in Example 2 using methyl 2,3,6-tri-O-benzyl-D-glucopyranoside as the compound containing a sugar structure. 90%).
¹ H-NMR (270MHz, CDCl _Three ) δ: 7.36-7.24 (m, 15H), 7.07 (d, 1H), 6.97 (m, 2H), 4.98 (d, 1H), 4.80-4.62 (m, 6H), 4.43 (d, 1H), 4.34 (d, 1H), 3.94 (t, 1H), 3.72-3.52 (m, 5H), 3.38 (s, 3H)
[0043]
Experimental Example 1: Removal of protecting group (synthesis of methyl 2,3,4-tri-O-benzyl-D-glucopyranoside)
Methyl 6-O- (4-azido-3-chlorobenzyl) -2,3,4-tri-O-benzyl-D-glucopyranoside (126 mg, 0.2 mmol) was dissolved in tetrahydrofuran (THF, 1 ml). PPh _Three (63 mg, 0.24 mmol) was added and stirred at room temperature for 1 hour. Subsequently, water (10 μl), glacial acetic acid (10 ml) and DDQ (68 mg, 0.3 mmol) were added to the reaction solution, and the mixture was further stirred for 1.5 hours. The reaction solution was diluted with ethyl acetate and washed with 5% ascorbic acid aqueous solution, saturated aqueous sodium hydrogen carbonate, and saturated brine. After drying over anhydrous sodium sulfate, the solvent was removed under reduced pressure to obtain a brown oil. Purification by silica gel column chromatography (eluent; dichloromethane: ethyl acetate = 40: 1) gave the title compound as a colorless oil (86 mg, yield 92%).
¹ H-NMR (270MHz, CDCl _Three ) δ: 7.37-7.24 (m, 15H), 4.99 (d, 1H), 4.90-4.77 (m, 3H), 4.65 (dd, 2H), 4.58 (d, 1H), 4.00 (t, 1H), 3.76 -3.62 (m, 3H), 3.55-3.47 (m, 2H), 3.36 (s, 3H), 1.63 (t, 1H)
Similar results were obtained by adding silica gel instead of acetic acid.
[0044]
Experimental Example 2: Acid resistance test
Methyl 6-O- (4-azido-3-chlorobenzyl) -2,3,4-tri-O-benzyl-D-glucopyranoside (the compound of Example 2) was dissolved in methylene chloride at room temperature in 2 equivalents of 3 Exposure to boron fluoride-diethyl ether did not decompose.
[2- (4-Methoxybenzyloxy) ethyl] benzene having a 4-methoxybenzyl group as a hydroxyl-protecting group, and methyl 6-O- (4-azidobenzyl) having a 4-azidobenzyl group as a hydroxyl-protecting group Similar experiments were performed using -2,3,4-tri-O-benzyl-D-glucopyranoside. As a result, [2- (4-methoxybenzyloxy) ethyl] benzene decomposes rapidly, and methyl 6-O- (4-azidobenzyl) -2,3,4-tri-O-benzyl-D-glucopyranoside is Decomposed about 25% in 6 hours.
From the above, it can be seen that the azidohalogenobenzyl group according to the present invention exhibits excellent stability against acids, unlike conventional hydroxyl protecting groups.
[0045]
Experimental Example 3: Selective detachment test
(1) Synthesis of ethylene glycol protected with an azidochlorobenzyl group and a methoxybenzyl group: Synthesis of 1-azido-2-chloro-4- (4-methoxybenzyloxyethoxymethyl) benzene
2- (4-Methoxybenzyloxy) ethanol (500 mg, 2.75 mmol) is dissolved in DMF (10 ml) and sodium hydride (60% in oil, 132 mg, 3.30 mmol) is added at 0 ° C. for 30 minutes. Stir. Subsequently, 4-azido-3-chlorobenzyl bromide (813 mg, 3.30 mmol) was added in portions. The reaction mixture was stirred at 0 ° C. for 30 minutes and at room temperature for 2 hours, ice water was added, and the mixture was extracted with ether. The ether layer was washed with water and then with saturated brine, and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (eluent; hexane: ethyl acetate = 10: 1) to give the title compound as a yellow oil (805 mg, yield). 84%).
¹ H-NMR (270MHz, CDCl _Three ) δ: 7.39 (d, 1H), 7.30-7.24 (m, 3H), 7.13 (d, 1H), 6.90-6.85 (m, 2H), 4.51 (s, 4H), 3.80 (s, 3H), 3.64 (s, 4H)
[0046]
(2) Removal of azidochlorobenzyl group: synthesis of 2- (4-methoxybenzyloxy) ethanol
1-azido-2-chloro-4- (4-methoxybenzyloxyethoxymethyl) benzene (174 mg, 0.5 mmol) obtained in (1) above was dissolved in THF (1 ml), and PPh was dissolved. _Three (157 mg, 0.6 mmol) was added, and the mixture was stirred at room temperature for 1 hour. Subsequently, water (10 ml), glacial acetic acid (10 ml) and DDQ (159 mg, 0.7 mmol) were added to the reaction solution, and the mixture was further stirred at room temperature for 1 hour. The reaction solution was diluted with ethyl acetate and washed with 5% ascorbic acid aqueous solution, saturated aqueous sodium hydrogen carbonate, and saturated brine. After drying over anhydrous sodium sulfate, the solvent was removed under reduced pressure, and the resulting brown oil was purified by silica gel column chromatography (eluent; dichloromethane: ethyl acetate = 2: 1) to give the title compound yellow Obtained as an oil (68 mg, 75% yield).
¹ H-NMR (270MHz, CDCl _Three ) δ: 7.27 (m, 2H), 6.89 (m, 2H), 4.49 (s, 2H), 3.81 (s, 3H), 3.74 (m, 2H), 3.57 (m, 2H)
[0047]
(3) Removal of methoxybenzyl group: synthesis of 2- (4-azido-3-chlorobenzyloxy) ethanol
1-azido-2-chloro-4- (4-methoxybenzyloxyethoxymethyl) benzene (348 mg, 1 mmol) obtained in (1) above was dissolved in THF (2 ml), and water (0.1 ml) was dissolved. And DDQ (34 mg, 1.50 mmol) were added, and the mixture was stirred at room temperature for 7 hours. The reaction solution was diluted with ethyl acetate, washed with 5% aqueous ascorbic acid solution, saturated aqueous sodium hydrogen carbonate and saturated brine, and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure, and the resulting brown oil was purified by silica gel column chromatography (eluent; hexane: ethyl acetate = 2: 1) to give the title compound as a yellow oil (201 mg, yield 88%).
¹ H-NMR (270MHz, CDCl _Three ) δ: 7.38 (d, 1H), 7.26 (m, 1H), 7.15 (d, 1H), 4.51 (s, 2H), 3.78 (t, 2H), 3.60 (t, 2H)
[0048]
As described above, the azidohalogenobenzyl group according to the present invention can be deprotected under conditions different from those of the conventional methoxybenzyl group. That is, DDQ and water alone do not deprotect the azidohalogenobenzyl group, but the methoxybenzyl group is deprotected, while PPh _Three , DDQ, water and acetic acid deprotect the azidohalogenobenzyl group, but not the methoxybenzyl group. Thus, by using the azidohalogenobenzyl group according to the present invention together with a conventional protecting group, the selective removal of the protecting group can be carried out.
[0049]
Examples 4 to 9 below are examples of sugar chain synthesis by the solid phase synthesis method using the protecting group of the present invention. In addition, the meaning of the symbol in reaction formula is as follows.
Bzl: benzyl
Ph: Phenyl
Trt: Triphenylmethyl
MPM: 4-methoxybenzyl
Bz: Benzoyl
Tce: 2,2,2-trichloroethyl
Troc: 2,2,2-trichloroethyloxycarbonyl
Et: ethyl
Bu: Butyl
Tf: trifluoromethylsulfonyl
Ac: Acetyl
[0050]
Example 4: Synthesis of phenyl 6-O- (4-azido-3-chlorobenzyl) -2,3,4-tri-O-benzyl-1-thio-D-glucopyranoside (4)
[0051]
[Chemical Formula 10]

[0052]
(A) Synthesis of 1,6-anhydro-2,3,4-tri-O-benzyl-β-D-glucopyranoside (2)
Sodium hydride (60% in oil, 13.2 g, 0.33 mol) was washed with anhydrous ether and suspended in DMF (100 ml). 1,6-Anhydro-β-D-glucopyranoside (1) (16.2 g, 0.1 mol) was added thereto and stirred at room temperature for 30 minutes. Next, the mixture was cooled to 0 ° C., benzyl bromide (39.3 ml, 0.33 mol) was added dropwise, and the mixture was stirred at room temperature for 2 hours. Water (200 ml) was added, and the mixture was extracted 3 times with ethyl acetate. The organic layers were combined, washed with saturated brine, and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure to obtain white crystals. Recrystallization from hot methanol gave 1,6-anhydro-2,3,4-tri-O-benzyl-β-D-glucopyranoside (2) as white crystals (38.2 g, yield 88%).
[0053]
(B) Synthesis of phenyl 2,3,4-tri-O-benzyl-1-thio-D-glucopyranoside (3)
1,6-Anhydro-2,3,4-tri-O-benzyl-β-D-glucopyranoside (2) (15.0 g, 34.7 mmol) and phenylthiotrimethylsilane (19.7 ml, 104 mmol) in dichloromethane solution (100 ml) was added zinc iodide (11.1 g, 34.7 mmol), and the mixture was stirred at room temperature for 4 hours. The reaction solution was filtered and the filtrate was concentrated under reduced pressure. The residue was dissolved in methanol (100 ml), 1N hydrochloric acid (50 ml) was added, and the mixture was stirred at room temperature for 15 min. Methanol was removed under reduced pressure, followed by extraction with ethyl acetate, and the organic layer was washed with a saturated aqueous sodium hydrogen carbonate solution and then with a saturated saline solution. After drying over anhydrous sodium sulfate, the solvent was removed under reduced pressure, and the resulting oil was crystallized in hexane to give white crystals of phenyl 2,3,4-tri-O-benzyl-1-thio-D-glucopyranoside. (3) was obtained (19.5 g, yield 89%).
[0054]
(C) Synthesis of phenyl 6-O- (4-azido-3-chlorobenzyl) -2,3,4-tri-O-benzyl-1-thio-D-glucopyranoside (4)
Sodium hydride (60% in oil, 96 mg) was added to a solution of phenyl 2,3,4-tri-O-benzyl-1-thio-D-glucopyranoside (3) (1.09 g, 2.00 mmol) in DMF (10 ml). 2.40 mmol) was added and stirred at room temperature for 15 minutes. The mixture was cooled to 0 ° C., 4-azido-3-chlorobenzyl bromide (592 mg, 2.40 mmol) was added, and the mixture was stirred at room temperature for 4 hours. Water (30 ml) was added, and the mixture was extracted twice with ethyl acetate. The organic layers were combined, washed with saturated brine, and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure, and the resulting residue was purified by silica gel column chromatography (eluent; hexane: ethyl acetate = 5: 1) to give slightly yellow crystalline phenyl 6-O- (4-azido-3- Chlorobenzyl) -2,3,4-tri-O-benzyl-1-thio-D-glucopyranoside (4) was obtained (1.33 g, 94% yield).
[0055]
Example 5: Synthesis of phenyl 6-O- (4-azido-3-chlorobenzyl) -2,3,4-tri-O-benzoyl-1-thio-β-D-glucopyranoside (11)
[0056]
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[0057]
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[0058]
(A) Synthesis of phenyl 6-O-triphenylmethyl-1-thio-β-D-glucopyranoside (6)
Phenyl 1-thio-β-D-glucopyranoside (5) (7.01 g, 25.8 mmol) and triphenylmethyl chloride (9.33 g, 33.5 mmol) were suspended in pyridine (20 ml) and refluxed for 5 hours. After removing the solvent under reduced pressure, the residue was dissolved in ethyl acetate, washed with water and then with saturated brine, and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure, and the resulting residue was purified by silica gel column chromatography (eluent; dichloromethane: ethyl acetate = 1: 1) to give phenyl 6-O-triphenylmethyl-1-thio-β as a white solid. -D-glucopyranoside (6) was obtained (13.1 g, yield 99%).
[0059]
(B) Synthesis of phenyl 2,3,4-tri-O- (4-methoxybenzyl) -6-O-triphenylmethyl-1-thio-β-D-glucopyranoside (7)
Phenyl 6-O-triphenylmethyl-1-thio-β-D-glucopyranoside (6) (13.0 g, 25.3 mmol) in DMF (80 ml) was added to sodium hydride (60% in oil, 3.22 g, 80.5 mmol). ) And stirred at room temperature for 20 minutes. The mixture was cooled to 0 ° C., 4-methoxybenzyl chloride (12.6 g, 80.5 mmol) was added, and the mixture was stirred at room temperature overnight. Cold water was added and extracted twice with ether, and the combined ether layers were washed with water and then with saturated brine. After drying over anhydrous sodium sulfate, the solvent was removed under reduced pressure, and the resulting residue was purified by silica gel column chromatography (eluent; hexane: ethyl acetate = 3: 1) to give a white oily phenyl 2,3,4 -Tri-O- (4-methoxybenzyl) -6-O-triphenylmethyl-1-thio-β-D-glucopyranoside (7) was obtained (18.8 g, yield 85%).
[0060]
(C) Synthesis of phenyl 2,3,4-tri-O- (4-methoxybenzyl) -1-thio-β-D-glucopyranoside (8)
Phenyl 2,3,4-tri-O- (4-methoxybenzyl) -6-O-triphenylmethyl-1-thio-β-D-glucopyranoside (7) (3.44 g, 3.93 mmol) in ether (8 ml) ) To the solution was added formic acid (8 ml) and stirred at room temperature for 5 hours. The reaction solution was washed with water, saturated aqueous sodium hydrogen carbonate solution and saturated brine in this order, and then the solvent was removed under reduced pressure. The residue was suspended in a mixture of ethanol (5 ml) and 1N aqueous sodium hydroxide solution (5 ml) and stirred overnight at room temperature. Ethanol was distilled off under reduced pressure, followed by extraction with ether twice. The combined ether layers were washed with saturated brine and then dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure, and the residue was purified by silica gel column chromatography (eluent; hexane: ethyl acetate = 2: 1 → 1: 1), and white crystalline phenyl 2,3,4-tri-O- ( 4-Methoxybenzyl) -1-thio-β-D-glucopyranoside (8) was obtained (1.28 g, yield 51%).
[0061]
(D) Synthesis of phenyl 6-O- (4-azido-3-chlorobenzyl) -2,3,4-tri-O- (4-methoxybenzyl) -1-thio-β-D-glucopyranoside (9)
Phenyl 2,3,4-tri-O- (4-methoxybenzyl) -1-thio-β-D-glucopyranoside (8) (1.25 g, 1.98 mmol), 4-azido-3-chlorobenzyl bromide (584 mg) , 2.37 mmol) in DMF (10 ml) was added sodium hydride (60% in oil, 95 mg, 2.37 mmol) and stirred at room temperature for 3 hours. Cold water was added, and the mixture was extracted twice with ether. The combined ether layer was washed with water and then with saturated brine, and then dried over anhydrous sodium sulfate. The residue obtained by removing the solvent under reduced pressure was purified by silica gel column chromatography (eluent; hexane: ethyl acetate = 4: 1), and white crystalline phenyl 6-O- (4-azido-3-chloro) was obtained. (Benzyl) -2,3,4-tri-O- (4-methoxybenzyl) -1-thio-β-D-glucopyranoside (9) was obtained (1.25 g, yield 79%).
[0062]
(E) Synthesis of phenyl 6-O- (4-azido-3-chlorobenzyl) -1-thio-β-D-glucopyranoside (10)
Phenyl 6-O- (4-azido-3-chlorobenzyl) -2,3,4-tri-O- (4-methoxybenzyl) -1-thio-β-D-glucopyranoside (9) (1.24 g, 1.55 mmol) in dichloromethane (10 ml) were added water (0.5 ml) and DDQ (1.41 g, 6.21 mmol) and stirred at room temperature for 3 hours. 5% L-ascorbic acid aqueous solution was added and stirred for a while, and then extracted with ethyl acetate. The organic layer was washed with a saturated aqueous solution of sodium bicarbonate and then with a saturated saline solution and then dried over anhydrous sodium sulfate. The residue obtained by removing the solvent under reduced pressure was purified by silica gel column chromatography (eluent; dichloromethane: ethyl acetate = 1: 3) to give yellow crystalline phenyl 6-O- (4-azido-3-chloro). (Benzyl) -1-thio-β-D-glucopyranoside (10) was obtained (584 mg, yield 86%).
[0063]
(F) Synthesis of phenyl 6-O- (4-azido-3-chlorobenzyl) -2,3,4-tri-O-benzoyl-1-thio-β-D-glucopyranoside (11)
To a solution of phenyl 6-O- (4-azido-3-chlorobenzyl) -1-thio-β-D-glucopyranoside (10) (580 mg, 1.32 mmol) in pyridine (5 ml) at 0 ° C., benzoyl chloride (609 μl, 5.28 mmol) was added, and the mixture was stirred at room temperature for 2 hours. Water was added and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure to give slightly yellow crystalline phenyl 6-O- (4-azido-3-chlorobenzyl) -2,3,4-tri-O-benzoyl-1-thio-β-D-glucopyranoside ( 11) was obtained (934 mg, 94% yield).
[0064]
Example 6: Synthesis of polystyrene resin derivative having 2,3,4-tri-O-benzyl-glucopyranoside of formula (17) immobilized thereon
[0065]
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[0066]
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[0067]
(A) Synthesis of 4-bromomethylphenylacetic acid 2,2,2-trichloroethyl ester (13)
4-Bromomethylphenylacetic acid (12) (10.3 g, 44.8 mmol) was suspended in dichloromethane (30 ml), trifluoroacetic anhydride (9.28 ml, 67.2 mmol) was added at 0 ° C., and the mixture was stirred for 30 minutes. Subsequently, 2,2,2-trichloroethanol (6.47 ml, 67.2 mmol) was added dropwise, and the mixture was stirred at room temperature overnight. The extract was washed with water, saturated aqueous sodium hydrogen carbonate solution and saturated brine, dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure to give a colorless oil. The oil was allowed to stand overnight to obtain white crystalline 4-bromomethylphenylacetic acid 2,2,2-trichloroethyl ester (13) (15.9 g, yield 98%).
[0068]
(B) Synthesis of 4- (4-hydroxymethylphenylacetoxymethyl) phenylacetic acid 2,2,2-trichloroethyl ester (14)
4-Bromomethylphenylacetic acid (12) (1.15 g, 5.00 mmol) was added to a solution of cesium carbonate (1.63 g, 5.00 mmol) in water (50 ml), and the mixture was refluxed for 1 hour. After cooling, the solution was concentrated to dryness under reduced pressure, and the resulting residue was suspended in DMF (10 ml). 4-Bromomethylphenylacetic acid 2,2,2-trichloroethyl ester (13) (1.80 g, 5.00 mmol) was added thereto, and the mixture was stirred at room temperature overnight. Water was added, extraction was performed with ethyl acetate, and the organic layer was washed with saturated brine. After drying over anhydrous sodium sulfate, the solvent was removed under reduced pressure, and the resulting oil was purified by silica gel column chromatography (eluent; dichloromethane: ethyl acetate = 15: 1) to give 4- (4-hydroxy) as a white solid. Methylphenylacetoxymethyl) phenylacetic acid 2,2,2-trichloroethyl ester (14) was obtained (994 mg, yield 45%).
[0069]
(C) Synthesis of 2,2,2-trichloroethyl ester derivative of formula (15)
4- (4-hydroxymethylphenylacetoxymethyl) phenylacetic acid 2,2,2-trichloroethyl ester (14) (1.94 g, 4.35 mmol), phenyl 2,3,4-tri-O-benzyl-6-O- (2,2,2-trichloroethyloxycarbonyl) -1-thio-D-glucopyranoside (2.94 g, 3.95 mmol), iodosobenzene (956 mg, 4.35 mmol), silver perchlorate (328 mg, 1.58 mmol) Molecular Sieve (registered trademark) 4A (about 1 g) was suspended in ether (15 ml) and stirred at room temperature for 30 minutes under a nitrogen atmosphere. The mixture was cooled to 0 ° C., trimethylsilyl chloride (101 μl, 0.79 mmol) was added, and the mixture was stirred for 30 minutes. The reaction solution was filtered, and the filtrate was washed with a saturated aqueous sodium hydrogen carbonate solution and then with a saturated saline solution, and then dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure, and the resulting residue was purified by silica gel column chromatography (eluent; hexane: ethyl acetate = 4: 1) to give the 2,2,2-trichloroethyl ester derivative of formula (15) colorless. Obtained as an oil (3.22 g, 77% yield). α-anomer / β-anomer = 95/5
[0070]
(D) Synthesis of carboxylic acid derivative of formula (16)
The 2,2,2-trichloroethyl ester derivative of formula (15) (3.22 g, 3.06 mmol) was dissolved in 90% acetic acid, powdered zinc (4.00 g, 61.1 mmol) was added, and the mixture was stirred at room temperature for 2 hours. The reaction solution was filtered, and the filtrate was diluted with ethyl acetate, washed with saturated brine, and dried over anhydrous sodium sulfate. The residue obtained by removing the solvent under reduced pressure was purified by silica gel column chromatography (eluent; dichloromethane: methanol = 97: 3) to obtain the carboxylic acid derivative of formula (16) as a white solid (2.11 g, Yield 93%).
[0071]
(E) Synthesis of polystyrene resin derivative of formula (17)
Carboxylic acid derivative of formula (16) (896 mg, 1.20 mmol), aminomethylated polystyrene resin (0.83 mmol / g, 1.20 g, 1 mmol), diisopropylcarbodiimide (DIC) (219 μl, 1.40 mmol), 1-hydroxybenzo Triazole (HOBt) (189 mg, 1.40 mmol) and triethylamine (195 μl, 1.40 mmol) were suspended in dichloromethane (10 ml) and shaken at room temperature for 2 hours. The resin was collected by filtration, washed with DMF and dichloromethane, and then dried under reduced pressure to obtain a polystyrene resin derivative of the formula (17) (1.88 g, yield about 100%).
[0072]
Example 7: Glycosylation reaction of polystyrene resin derivative of formula (17) and 4-azido-3-chlorobenzylated thioglycoside of formula (4) or formula (11)
[0073]
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[0074]
Thioglycoside (75 mmol) of formula (4) (R = benzyl) or formula (11) (R = benzoyl) obtained in Example 4 or Example 5, of formula (17) obtained in Example 6. Polystyrene resin derivative (25 mmol), tetrabutylammonium salt (25 mmol) (when R = benzyl, tetrabutylammonium perchlorate was used, and when R = benzoyl, tetrabutylammonium trifluoromethanesulfonate was used) and Molecular sieve (registered trademark) 4A was suspended in dichloromethane (1 ml) and shaken for 15 minutes. N-bromosuccinimide (15 mg, 83 mmol) was added thereto, and the mixture was shaken overnight at room temperature. Molecular sieve (registered trademark) 4A was removed, and the resin was collected by filtration, washed with dichloromethane, and then dried under reduced pressure to obtain a polystyrene resin derivative of formula (18). The introduction ratio of 4-azido-3-chlorobenzylated glycoside into the resin was 30 to 75%. When the introduction rate is low, the reaction may be repeated 2-3 times.
[0075]
Example 8: Removal of 4-azido-3-chlorobenzyl group from polystyrene resin derivative of formula (18)
[0076]
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[0077]
Polystyrene resin derivatives of formula (18) containing hydroxyl groups protected with 4-azido-3-chlorobenzyl groups (about 70 mg, 10-15 μmol of 4-azido-3-chlorobenzyl groups are present) and PPh _Three (20 mg, 75 μmol) was added to THF (1 ml) and shaken at room temperature for 1.5 hours. The resin was collected by filtration, washed with THF, and the resin was added again to THF (1 ml). To this, DDQ (8.5 mg, 37.5 μmol) and 50% aqueous acetic acid solution (20 μl) were added and shaken at room temperature for 3 hours. The resin was collected by filtration, washed with DMF and then dichloromethane, and dried under reduced pressure to quantitatively obtain a polystyrene resin derivative of the formula (19).
[0078]
Example 9: Glycosylation reaction of polystyrene resin derivative of formula (19) and 4-azido-3-chlorobenzylated thioglycoside of formula (4) or formula (11)
[0079]
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[0080]
Thioglycoside (75 mmol) of formula (4) (R = benzyl) or formula (11) (R = benzoyl), polystyrene resin derivative (8 mmol) of formula (19), tetrabutylammonium salt (25 mmol) (R = Tetrabutylammonium perchlorate when = benzyl, tetrabutylammonium trifluoromethanesulfonate when R = benzoyl) and molecular sieve 4A were suspended in dichloromethane (1 ml) Shake for 15 minutes. N-bromosuccinimide (15 mg, 83 mmol) was added thereto, and the mixture was shaken overnight at room temperature. Molecular sieve (registered trademark) 4A was removed, and the resin was collected by filtration, washed with dichloromethane, and then dried under reduced pressure to obtain a polystyrene resin derivative of formula (20). The introduction ratio of 4-azido-3-chlorobenzylated glycoside into the resin was 33%.
[0081]
【The invention's effect】
As described above, by arranging an azide group on the benzyl group, the protective group can be easily removed under mild conditions by reducing it to an amino group when necessary, The arranged halogeno group improves the acid resistance. Therefore, the azidohalogenobenzyl group according to the present invention is useful as a stable hydroxyl-protecting group, particularly in solid-phase synthesis in which it is continuously placed in an acidic environment for sugar chain elongation. Further, according to the present invention, an azidohalogenobenzyl derivative capable of introducing such an azidohalogenobenzyl group, a sugar compound protected using the derivative, and a method for protecting a hydroxyl group using the derivative can be provided.

Claims (6)

Formula (I)

Ajidoharogeno that (In the formula, A a halogen atom, B is a water atom, X is indicates a halogen atom, respectively, N ₃ group is attached to o-position or p-position of the benzene ring) represented by Benzyl derivatives.   The azidohalogenobenzyl derivative according to claim 1, which is 4-azido-3-chlorobenzyl bromide. Formula (I)

Ajidoharogeno that (In the formula, A a halogen atom, B is a water atom, X is indicates a halogen atom, respectively, N ₃ group is attached to o-position or p-position of the benzene ring) represented by By reacting a benzyl derivative with a hydroxyl group-containing compound, the hydrogen atom of the hydroxyl group of the hydroxyl group-containing compound is converted to the general formula (II)

(In the formula, A a halogen atom, B is shows the water atom respectively, N ₃ group is attached to o-position or p-position of the benzene ring) to replace the azidohalogenobenzyl group represented by A method for protecting a hydroxyl group characterized by the following. The protection method according to claim 3 , wherein the hydroxyl group-containing compound is a compound containing a sugar structure. Formula (I)

Ajidoharogeno that (In the formula, A a halogen atom, B is a water atom, X is indicates a halogen atom, respectively, N ₃ group is attached to o-position or p-position of the benzene ring) represented by A reagent for protecting a hydroxyl group, containing a benzyl derivative. The reagent according to claim 5 , wherein the azidohalogenobenzyl derivative is 4-azido-3-chlorobenzyl bromide.